fix many internal links

Fixed a number of internal links that need to
go to the GitHub site.

Ran `make www` to perform the above.

2012/deckmyn/index.html

@@ -427,12 +427,12 @@ etc.</p>
 <p>The program expects <em>two command line arguments</em>. The first is a (very long)
 string that contains the complete music font. Note that it should <em>not</em> be given
 as a file name! The default music font is encoded in the (whitespace of the)
-source code <a href="deckmyn.c">deckmyn.c</a> itself. Therefore, the first argument should
+source code <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2012/deckmyn/deckmyn.c">deckmyn.c</a> itself. Therefore, the first argument should
 be <code>"``</code> <code>cat deckmyn.c</code> <code>``"</code>.</p>
 <p>The second command line argument is the music itself. This is, again, a string,
 not a file name. All music signs are entered as tokens of exactly 3 characters.
 The code is very sensitive to bad spacing! So for instance, if you use a file to
-write the music (e.g. <a href="example_greensleeves">example_greensleeves</a>), you should
+write the music (e.g. <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2012/deckmyn/example_greensleeves">example_greensleeves</a>), you should
 keep in mind that newline is also a character!</p>
 <h3 id="internals">Internals</h3>
 <p>To minimise the memory footprint, this program has <em>no variable declarations at