added contactPairTest to btCollisionWorld
removed NO_DYNAMIC_EXECUTION from make.py in order to make ConcreteContactResultCallback work
added convexSweepTest and related classes to btCollisionWorld
added collision group and mask attributes to RayResultCallback and ConvexResultCallback
added btHingeConstraint
added setWorldTransform to  btCollisionObject
added btGeneric6DofConstraint and btGeneric6DofSpringConstraint
added m_closestHitFraction to ConvexResultCallback
added graphicsWorldTrans to btDefaultMotionState