improve display_via_github and display_as values

Fixed some inconsistent use of display_via_github and display_as values.

2013/hou/index.html

@@ -358,8 +358,8 @@ frequently found in other <code>PPM</code> implementations.</p></li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2013/hou/Makefile">Makefile</a> - entry Makefile</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2013/hou/hou.orig.c">hou.orig.c</a> - original source</li>
 <li><a href="doc/example.html">doc/example.html</a> - detailed information about entry</li>
-<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2013/hou/old_default.scene">old_default.scene</a> - sample input</li>
-<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2013/hou/otherroom.scene">otherroom.scene</a> - sample input</li>
+<li><a href="old_default.scene">old_default.scene</a> - sample input</li>
+<li><a href="otherroom.scene">otherroom.scene</a> - sample input</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2013/hou/try.sh">try.sh</a> - how to run</li>
 <li><a href="luna.jpg">luna.jpg</a> - sample image data</li>
 <li><a href="old_default.jpg">old_default.jpg</a> - sample image data</li>