Initial work on LUA scripting.

This LUA scripting implementation uses the sol header only C++ wrapper for the native LUA libraries.

The API does not follow the original LU scripting. Each instance of a script is in its own LUA-State, and has 'self' as a global. There are hooks to all the implemented CppScript methods, as well as a subset of the entity functionallity. Has to be expanded upon.

This is local work which has been sitting for awhile; thought someone might like to take a look at it.

dScripts/CppScripts.h

@@ -320,6 +320,7 @@ namespace CppScripts {
                                        float_t pathTime, float_t totalTime, int32_t waypoint) {};
 	};
 
+	Script* GetInvalidScript();
 	Script* GetScript(Entity* parent, const std::string& scriptName);
 	std::vector<Script*> GetEntityScripts(Entity* entity);
 };