Ai fix

Ai mach vanilla behavior more closely. Still, I don't like the castRay(const Ogre::Vector3& from, const Ogre::Vector3& to, bool raycastingObjectOnly = true,bool ignoreHeightMap = false); interface. Scrawl suggested to bring enum CollisionType from physic.hpp to physicsystem.hpp and put collision filter as argument instead, but that would make physic.hpp dependent on physicsystem.hpp ...

What do you think?