think about adding support for passing multiple values into, and out of lua

[Tomasu]

Based on Had's fork, std::tuple can be used to allow returning multiple values from a bound function to lua.

allowing things like: local a,b,c = obj:my_c_func();

[Tomasu]

see https://github.com/had/LuaGlue/commit/b284efcb5b7b9781af32b6e0af5e9ae434fb181d