1) creating a broadphase proxy -> adding pairs during insertion. But during this pair insertion, the btGhostObject broadphase handle isn't set yet (it is done in step 2)
2) assign the broadphase proxy to btGhostObject
Thanks to ihar3d for the report http://bulletphysics.com/Bullet/phpBB3/viewtopic.php?f=9&t=2864
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.
