Fix mobile menus and add to menus

The mobile About menu was missing the IOCCC markdown guidelines. This
has been added to the mobile menu but moved to 'Status' which is where
guidelines are (it has been renamed to be 'IOCCC Markdown Guidelines' to
match the style of the other items in that menu).

The About menu now has two more links, one for the website tools and the
other for the include files of the tools. It might be, looking at the
generated html files, better to have another menu instead, but what that
should be is unclear. The reason it might be better is because the
'About' menu is rather long. In retrospect it might be better to not
have the script include files in the html files but this can be decided
and dealt with later.

The script bin/find-missing-links.sh now ignores the directory NOTES/. A
better approach might be using git ls-files --exclude but a quick test
did not work right. Another option, at least for NOTES/, might be to use
'git ls-files --exclude-standard'.

The bin/index.html file has been updated.

Run make www to rebuild all html files.

2015/index.html

@@ -109,6 +109,12 @@
                 Rules and Guidelines
               </a>
             </div>
+
+            <div class="outfit-font">
+              <a href="../markdown.html" class="sub-item-link">
+                IOCCC Markdown Guidelines
+              </a>
+            </div>
           </div>
         </div>
 
@@ -187,8 +193,14 @@
             </div>
 
             <div class="outfit-font">
-              <a href="../markdown.html" class="sub-item-link">
-                IOCCC markdown guidelines
+              <a href="../bin/index.html" class="sub-item-link">
+                Website scripts
+              </a>
+            </div>
+
+            <div class="outfit-font">
+              <a href="../inc/index.html" class="sub-item-link">
+                Script include files
               </a>
             </div>
           </div>
@@ -267,6 +279,10 @@
               IOCCC News
             </a>
 
+            <a class="mobile-submenu-item" href="../markdown.html">
+              IOCCC Markdown Guidelines
+            </a>
+
           </div>
         </div>
 
@@ -321,6 +337,13 @@
               Thanks for the help
             </a>
 
+            <a class="mobile-submenu-item" href="../bin/index.html">
+              Website scripts
+            </a>
+
+            <a class="mobile-submenu-item" href="../inc/index.html">
+              Script include files
+            </a>
           </div>
         </div>