Removed an unused file.
Removed internal methods from public cLuaState interface.

PushFunction(), CallFunction() and GetReturn() are not to be called independently, but rather only by using the Call() templated overrides.
Push() needs to be left in the public part, it is used for pushing results in the ManualBindings.

Preparation for #418.
Lua errors display stack trace.

Fixes #418.
Merge pull request #532 from mc-server/LuaStateErrorHandler

Lua state error handler