Added support for code reloading and coroutine debugging under LuaJIT.

This requires using a version of LuaJIT that include this commit
(http://repo.or.cz/w/luajit-2.0.git/commit/e422ae2d9d184592066c1252ba0b391c4a1830ba);
the test case and related discussions: http://www.freelists.org/post/luajit/Issues-with-using-error-in-debug-hook,1
Added support for cross-platform remote debugging.
Updated README and formatting.