Merge branch 'master' into v2.1

doc/contact.html

@@ -61,8 +61,15 @@
 </div>
 <div id="main">
 <p>
+If you want to report bugs, propose fixes or suggest enhancements,
+please use the
+<a href="https://github.com/LuaJIT/LuaJIT/issues">GitHub issue tracker</a>.
+</p>
+<p>
 Please send general questions to the
 <a href="http://luajit.org/list.html"><span class="ext">&raquo;</span>&nbsp;LuaJIT mailing list</a>.
+</p>
+<p>
 You can also send any questions you have directly to me:
 </p>