* po.pointInside(po, x, y) as a wrapper for P_PointInsidePolyobj
* po.mobjTouching(po, mo) as a wrapper for P_MobjTouchingPolyobj
* po.mobjInside(po, mo) as a wrapper for P_MobjInsidePolyobj
I can confirm that ":" syntax works with all the above, e.g. po:mobjInside(mo)
* create new file lua_polyobjlib.c
* made a stub LUA_PolyObjLib function
* added META_POLYOBJ to lua_libs.h
* updated makefile, CMake and MSVC project files for lua_polyobjlib.c