updates luacppbridge51

Original commit:
commit c728eec4c6db9f5e3c8cd12a1fd30bc08b700062
Author: Ignacio Burgueño <ignaciob@inconcertcc.com>
Date:   Wed Jul 23 19:55:19 2014 -0300

    Adds __name field to exposed classes' metatable.

    Each exposed class has a metatable. The '__name' field is added to it, and
    it has the exposed class 'className'.
    This way, we can know the className from the metatable (which wasn't possible
    just by looking at its members in some cases).