A couple of fixes on Door class:

A couple of fixes on Door class:
- door images were being stored for each object (IMO door game object, should be putted together with the others. This way, wouldn't be needed to add stuff into resources.cpp directly, but to load_objects_gfx() func);
- animation was not working properly (could be added to Sprite one time animations).

SVN-Revision: 1503