Add scripts to build luajit for iOS and OSX
Update libmoai Xcode project for LuaJIT builds

* Separate Lua compilation into its own target
    * Two new targets: libmoai-ios-lua and libmoai-osx-lua
* Adding new variable for enabling/disabling luajit
Update osx and ios projects to use LuaJIT
Update Xcode project readme

* Change format to markdown
* Add information on how to switch to non JIT compilation
Update the luajit build scripts

* Remove commented out code
* Add input args for product name and destination to tie into xcode
target
Update libmoai Xcode project w/luajit targets

* Add LuaJIT targets for iOS and OSX
* Remove old luajit compile scripts in libmoai-ios and libmoai-osx
Update iOS Project with luajit target

* Add moai-luajit for building with jit
* Use existing moai target for building without jit
* Adding scheme for JIT
Update OSX Project with LuaJIT target

* Add moai-luajit target for JIT builds
* Use existing moai target for non JIT builds
* Add scheme for JIT builds.
Remove LuaJIT portion of the Xcode readme

Guide to non-LuaJIT build is no longer needed with the separate schemes
for Lua and LuaJIT builds.
Merge pull request #775 from JandyCo/luajit-mac

Add LuaJIT support on iOS and OS X