Remove almost all absolute URLs for this site

In a number of cases, an absolute URL for www.ioccc.org
was replaced with a document root relative URL.

In some cases the absolute URL was removed.

Removed mirror request pages.

2015/burton/hint.html

@@ -69,7 +69,8 @@ See the included man page. ;-)</p>
 <h2>Notes</h2>
 
 <p>This program is named calc.  Onomatopoeia of sorts, in the visual realm.
-The formatting was easier: Form Follows Function (although <a href="http://www.ioccc.org/2011/hou/hint.html" title="Hou Qiming">Hou</a> did this better).
+The formatting was easier: Form Follows Function (although the 2011 <a href="/2011/hou/hint.html" title="Hou Qiming">Hou</a> entry
+did this better).
 It was tempting to call it iCalc, with i for integer (and it was written on an iDevice),
 but sanity prevailed.</p>