first lua work - see #26

still at least need to:
* reorganize Interpreter.cpp
* display the stack trace in case of error
* add an option to statically link with lua and luabind
move language specific code in their own dir
display stack trace in case of error in lua script

used the method described in http://lua-users.org/lists/lua-l/2013-12/msg00360.html
better handling of python error - still need to do better than that though
properly deal with error reports in python