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.

1996/schweikh3/README.md

@@ -131,7 +131,7 @@ situation and effectively halts.
 I had the pleasure and pain to find all three behaviours on the
 platforms I use regularly.
 
-The file [schweikh3.info](schweikh3.info) has output for
+The file [schweikh3.info](%%REPO_URL%%/1996/schweikh3/schweikh3.info) has output for
 Solaris, FreeBSD and Linux. The Linux case is interesting in that
 the behaviour changes when `calloc(3)` is used instead of `malloc(3)`.
 For FreeBSD, the last two lines are not messages stemming from

1996/schweikh3/index.html

@@ -463,7 +463,7 @@ situation and effectively halts.</p></li>
 </ol>
 <p>I had the pleasure and pain to find all three behaviours on the
 platforms I use regularly.</p>
-<p>The file <a href="schweikh3.info">schweikh3.info</a> has output for
+<p>The file <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1996/schweikh3/schweikh3.info">schweikh3.info</a> has output for
 Solaris, FreeBSD and Linux. The Linux case is interesting in that
 the behaviour changes when <code>calloc(3)</code> is used instead of <code>malloc(3)</code>.
 For FreeBSD, the last two lines are not messages stemming from