Fix Luajit on 64-bit OSX

- Luajit has specific linker requirements on 64-bit OSX. See
  http://luajit.org/install.html .. It doesn't work without this!
Merge pull request #200 from justfalter/fix_lua_64bit_osx

Fix Luajit on 64-bit OSX
Improvements to cmake building

- Move cmake modules/scripts to safer locations
- Enforce out-of-source builds
Learn how to spell "clean"
Merge pull request #201 from justfalter/cmake_cleanup

Cmake cleanup