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.

2014/sinon/README.md

@@ -1,13 +1,13 @@
 ## To build:
 
-```sh
+```<!---sh-->
     make
 ```
 
 
 ## To use:
 
-```sh
+```<!---sh-->
     ./hecate.sh
 
     ./glock.sh
@@ -16,7 +16,7 @@
 
 ## Try:
 
-```sh
+```<!---sh-->
     ./try.sh
 ```
 
@@ -41,7 +41,7 @@ under one minute.
 To start, compile and run the program.  To resume, compile and run the
 output repeatedly until you have won/lost the game.  For example:
 
-```sh
+```<!---sh-->
     cp prog.c run.c
     gcc -O0 run.c -o run && ./run | tee run.c
     gcc -O2 run.c -o run && ./run | tee run.c
@@ -106,7 +106,7 @@ a primary input.
 that there are no files named "run" and "run.c" in current directory
 (they will be overwritten) and run:
 
-```sh
+```<!---sh-->
     perl prog.c | bash
 ```