Added btGhostObject and btPairCachingGhostObject functionality.

It is a fast way to keep track of overlapping objects in an area, and doing rayTest and convexSweepTest for overlapping objects, instead of btCollisionWorld::rayTest/convexSweepTest.

Updated KinematicCharacterController to use btPairCachingGhostObject.

src/BulletCollision/CollisionDispatch/btCollisionCreateFunc.h

@@ -17,7 +17,6 @@ subject to the following restrictions:
 #define COLLISION_CREATE_FUNC
 
 #include "LinearMath/btAlignedObjectArray.h"
-typedef btAlignedObjectArray<class btCollisionObject*> btCollisionObjectArray;
 class btCollisionAlgorithm;
 class btCollisionObject;