add hack-a-round for language specified markdown code blocks

When language is specified in a markdown code block such as:

````
```c
    printf("Hello, world!\n");
```
````

is used, the resulting HTML as produced by `pandoc(1)` combined
with our revised `ioccc.css` is not intent the code block well.

A temporary "_hack-a-round_" is to turn the "markdown code language
specifier" into an HTML comment.  For example:

````
```<!---c-->
    printf("Hello, world!\n");
```
````

This commits turns off existing markdown code language specifiers
for now, while preserving our ability to restore them in the future
when a better  "_hack-a-round_" to the "markdown code language
specifier" problem is found.

The HTML impact if this "_hack-a-round_" is to produce HTML that
looks like this:

```
<pre class="&lt;!---c--&gt;"><code> .. </code></pre>
```

We might be able to create a complex set of classes for each markdown
code language (there won't be very many) in `ioccc.css`, or we might
find a more general CSS (or maybe `pandoc(1)`?) solution.

For now, this hack-a-round will have to do.

2013/dlowe/README.md

@@ -1,6 +1,6 @@
 ## To build:
 
-```sh
+```<!---sh-->
     make
 ```
 
@@ -18,7 +18,7 @@ For more detailed information see [2013 dlowe bugs](../../bugs.html#2013_dlowe).
 
 ## To use:
 
-```sh
+```<!---sh-->
     ./dlowe [number...]
 ```
 
@@ -27,13 +27,13 @@ where `[number...]` is one or more number, space separated.
 
 ## Try:
 
-```sh
+```<!---sh-->
     ./try.sh
 ```
 
 What is different about the above if you do something like:
 
-```sh
+```<!---sh-->
     echo 'IOCCC winning entry 2013/dlowe' > ioccc.txt
     ./try.sh
     rm -f ioccc.txt
@@ -43,7 +43,7 @@ What is different about the above if you do something like:
 
 To make it simpler to see try showing just the different line like:
 
-```sh
+```<!---sh-->
     ./diff.sh
 ```
 
@@ -58,7 +58,7 @@ with one argument or when all arguments are equal?
 
 For extra fun, compile and run [fun.c](fun.c):
 
-```c
+```<!---c-->
     #include <stdio.h>
     int main() {
 	printf("%d %d %d\n", (int)(-1.0/0.0), (int)(0.0/0.0), (int)(1.0/0.0));
@@ -91,7 +91,7 @@ Which one is correct? :)
 NOTE: `make all` will compile [fun.c](fun.c) but to provide a different compiler
 you can do something like:
 
-```sh
+```<!---sh-->
     make CC=clang fun
 ```
 
@@ -105,7 +105,7 @@ A tiny implementation of command-line
 
 ### Synopsis
 
-```sh
+```<!---sh-->
     $ ./sparkl 0 1 2 3 4 5 6 7
     ▁▂▃▄▅▆▇▉
 
@@ -115,7 +115,7 @@ A tiny implementation of command-line
 
 NOTE: this has been provided in [slflen.sh](slflen.sh) so you can try:
 
-```sh
+```<!---sh-->
     ./slflen.sh
 ```
 

2013/dlowe/index.html

@@ -141,33 +141,33 @@ Location: <a href="../../location.html#US">US</a> - <em>United States of America
 <!-- START: this line starts content for HTML phase 21 by: bin/pandoc-wrapper.sh via bin/md2html.sh -->
 
 <h2 id="to-build">To build:</h2>
-<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a>    <span class="fu">make</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    make</code></pre>
 <h3 id="bugs-and-misfeatures">Bugs and (Mis)features:</h3>
 <p>The current status of this entry is:</p>
 <pre><code>    STATUS: INABIAF - please **DO NOT** fix</code></pre>
 <p>For more detailed information see <a href="../../bugs.html#2013_dlowe">2013 dlowe bugs</a>.</p>
 <h2 id="to-use">To use:</h2>
-<div class="sourceCode" id="cb3"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb3-1"><a href="#cb3-1" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./dlowe</span> <span class="pp">[</span><span class="ss">number...</span><span class="pp">]</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./dlowe [number...]</code></pre>
 <p>where <code>[number...]</code> is one or more number, space separated.</p>
 <h2 id="try">Try:</h2>
-<div class="sourceCode" id="cb4"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb4-1"><a href="#cb4-1" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./try.sh</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./try.sh</code></pre>
 <p>What is different about the above if you do something like:</p>
-<div class="sourceCode" id="cb5"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb5-1"><a href="#cb5-1" aria-hidden="true" tabindex="-1"></a>    <span class="bu">echo</span> <span class="st">&#39;IOCCC winning entry 2013/dlowe&#39;</span> <span class="op">&gt;</span> ioccc.txt</span>
-<span id="cb5-2"><a href="#cb5-2" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./try.sh</span></span>
-<span id="cb5-3"><a href="#cb5-3" aria-hidden="true" tabindex="-1"></a>    <span class="fu">rm</span> <span class="at">-f</span> ioccc.txt</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    echo &#39;IOCCC winning entry 2013/dlowe&#39; &gt; ioccc.txt
+    ./try.sh
+    rm -f ioccc.txt</code></pre>
 <p>?</p>
 <p>To make it simpler to see try showing just the different line like:</p>
-<div class="sourceCode" id="cb6"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb6-1"><a href="#cb6-1" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./diff.sh</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./diff.sh</code></pre>
 <h2 id="judges-remarks">Judges’ remarks:</h2>
 <p>We liked how this entry used Unicode, specifically UTF-8, in a somewhat
 obfuscated way.</p>
 <p>Also, why doesn’t it crash but instead produces a correct output when called
 with one argument or when all arguments are equal?</p>
 <p>For extra fun, compile and run <a href="fun.c">fun.c</a>:</p>
-<div class="sourceCode" id="cb7"><pre class="sourceCode c"><code class="sourceCode c"><span id="cb7-1"><a href="#cb7-1" aria-hidden="true" tabindex="-1"></a>    <span class="pp">#include </span><span class="im">&lt;stdio.h&gt;</span></span>
-<span id="cb7-2"><a href="#cb7-2" aria-hidden="true" tabindex="-1"></a>    <span class="dt">int</span> main<span class="op">()</span> <span class="op">{</span></span>
-<span id="cb7-3"><a href="#cb7-3" aria-hidden="true" tabindex="-1"></a>        printf<span class="op">(</span><span class="st">&quot;</span><span class="sc">%d</span><span class="st"> </span><span class="sc">%d</span><span class="st"> </span><span class="sc">%d\n</span><span class="st">&quot;</span><span class="op">,</span> <span class="op">(</span><span class="dt">int</span><span class="op">)(-</span><span class="fl">1.0</span><span class="op">/</span><span class="fl">0.0</span><span class="op">),</span> <span class="op">(</span><span class="dt">int</span><span class="op">)(</span><span class="fl">0.0</span><span class="op">/</span><span class="fl">0.0</span><span class="op">),</span> <span class="op">(</span><span class="dt">int</span><span class="op">)(</span><span class="fl">1.0</span><span class="op">/</span><span class="fl">0.0</span><span class="op">));</span></span>
-<span id="cb7-4"><a href="#cb7-4" aria-hidden="true" tabindex="-1"></a>    <span class="op">}</span></span></code></pre></div>
+<pre class="&lt;!---c--&gt;"><code>    #include &lt;stdio.h&gt;
+    int main() {
+        printf(&quot;%d %d %d\n&quot;, (int)(-1.0/0.0), (int)(0.0/0.0), (int)(1.0/0.0));
+    }</code></pre>
 <p>with gcc and clang.</p>
 <p>With GCC (4.7.2), we get</p>
 <pre><code>    -2147483648 -2147483648 -2147483648</code></pre>
@@ -178,19 +178,19 @@ with one argument or when all arguments are equal?</p>
 <p>Which one is correct? :)</p>
 <p>NOTE: <code>make all</code> will compile <a href="fun.c">fun.c</a> but to provide a different compiler
 you can do something like:</p>
-<div class="sourceCode" id="cb11"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb11-1"><a href="#cb11-1" aria-hidden="true" tabindex="-1"></a>    <span class="fu">make</span> CC=clang fun</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    make CC=clang fun</code></pre>
 <h2 id="authors-remarks">Author’s remarks:</h2>
 <h3 id="sparkl">sparkl</h3>
 <p>A tiny implementation of command-line
 <a href="https://en.wikipedia.org/wiki/Sparkline">sparkline</a> data visualization.</p>
 <h3 id="synopsis">Synopsis</h3>
-<div class="sourceCode" id="cb12"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb12-1"><a href="#cb12-1" aria-hidden="true" tabindex="-1"></a>    <span class="ex">$</span> ./sparkl 0 1 2 3 4 5 6 7</span>
-<span id="cb12-2"><a href="#cb12-2" aria-hidden="true" tabindex="-1"></a>    <span class="ex">▁▂▃▄▅▆▇▉</span></span>
-<span id="cb12-3"><a href="#cb12-3" aria-hidden="true" tabindex="-1"></a></span>
-<span id="cb12-4"><a href="#cb12-4" aria-hidden="true" tabindex="-1"></a>    <span class="ex">$</span> echo <span class="st">&quot;sparkline of file lengths: </span><span class="va">$(</span><span class="fu">wc</span> <span class="at">-c</span> <span class="pp">*</span> <span class="kw">|</span> <span class="fu">awk</span> <span class="st">&#39;{print $1}&#39;</span> <span class="kw">|</span> <span class="fu">xargs</span> ./sparkl<span class="va">)</span><span class="st">&quot;</span></span>
-<span id="cb12-5"><a href="#cb12-5" aria-hidden="true" tabindex="-1"></a>    <span class="ex">sparkline</span> of file sizes: ▁▁▁▃▃▂▁▂▁▁▉</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    $ ./sparkl 0 1 2 3 4 5 6 7
+    ▁▂▃▄▅▆▇▉
+
+    $ echo &quot;sparkline of file lengths: $(wc -c * | awk &#39;{print $1}&#39; | xargs ./sparkl)&quot;
+    sparkline of file sizes: ▁▁▁▃▃▂▁▂▁▁▉</code></pre>
 <p>NOTE: this has been provided in <a href="slflen.sh">slflen.sh</a> so you can try:</p>
-<div class="sourceCode" id="cb13"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb13-1"><a href="#cb13-1" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./slflen.sh</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./slflen.sh</code></pre>
 <p>instead (which <a href="try.sh">try.sh</a> also uses).</p>
 <h3 id="description">Description</h3>
 <p>This is a handy little tool for visualizing numeric series from the