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.

2015/burton/index.html

@@ -434,7 +434,7 @@ and hex input.</p>
 <p>Flow control is by <code>for</code> and <code>return</code>. It is <code>if</code>-less, <code>switch</code>-less,
 <code>while</code>-less, and hopeless. Literally, if not figuratively. ;-)</p>
 <p>The code size is intentionally 2015, as stated by <code>iocccsize -i</code>, and can be
-reformatted without changes (as in <a href="rule2.c">rule2.c</a>) to exactly 4096 octets.</p>
+reformatted without changes (as in <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/burton/rule2.c">rule2.c</a>) to exactly 4096 octets.</p>
 <p>Finally, <code>calc</code> is interesting, if for no other reason than it is practically
 useful: Hex/decimal conversion, arithmetic, byte-swapping, bit-shifting, and
 logical operations with memory, on the command line, or interactively.</p>