fix topbar to work on mobile devices

The topbar, by way of JavaScript, now works
on mobile devices such as cell phones and
tablets.

Internal links for entries from 1984 thru 2015
have been adjusted.

Ran `make www` to perform the above.

TODO: Fix some color issues on topbar.

TODO: More testing!

2015/endoh4/README.md

@@ -25,7 +25,7 @@ code](#alternate-code) below for details.
 
 ## Alternate code:
 
-An alternate version of this entry, [prog.alt.c](prog.alt.c), is provided.
+An alternate version of this entry, [prog.alt.c](%%REPO_URL%%/2015/endoh4/prog.alt.c), is provided.
 This alternate code does not contain improvements suggested by [Gil
 Dogon](../../authors.html#Gil_Dogon); it is the author's original entry.
 
@@ -68,7 +68,7 @@ Visual factorization 1-liner.  Try:
 Inspired by [Animated Factorization
 Diagrams](http://www.datapointed.net/visualizations/math/factorization/animated-diagrams/).
 
-[prog.alt.c](prog.alt.c) is the original version that I submitted. [Gil
+[prog.alt.c](%%REPO_URL%%/2015/endoh4/prog.alt.c) is the original version that I submitted. [Gil
 Dogon](../../authors.html#Gil_Dogon) kindly improved it during the review.  Thank
 you!