Lua table implementation

A new class, LuaTable, which allows to access Lua tables from C++ without loading all the table. It is an important performance issue to avoid duplicating memory between Lua and in C++, and this class is implemented to put Lua closer to C++. In this way, it is possible to work in Lua using tables and put its data into C++ without any overhead. It is used intensively to share weight matrix tables in ANN components.