update index.html and .entry.json per recent manifest changes

Every index.html file (for entries) was updated as the tarball download
description was changed to 'download entry source' (though I think this
is a mistake as the C file is described as 'entry source' so it's
ambiguous - that might be fixed soon or it mightn't be until some other
changes are made that need a manifest update).

2015/muth/index.html

@@ -228,7 +228,7 @@ https://creativecommons.org/licenses/by-sa/4.0/</p>
 <li><a href="index.html">index.html</a> - entry home page</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/muth/prog.c">prog.c</a>
-- winning source</li>
+- entry source</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/muth/Makefile">Makefile</a>
 - entry Makefile</li>
@@ -283,7 +283,7 @@ href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/muth/tape_em
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/muth/tape_five.h">tape_five.h</a>
 - cpp macros</li>
-<li><a href="2015_muth.tar.bz2">2015_muth.tar.bz2</a> - download winning
+<li><a href="2015_muth.tar.bz2">2015_muth.tar.bz2</a> - download entry
 source</li>
 </ul>
 <h2 id="secondary-files">Secondary files</h2>