pass collision shapes as const. fixed some issues with continuous convex cast (resulting hitnormal was not initialized properly, results not proper)

src/BulletCollision/NarrowPhaseCollision/btGjkEpaPenetrationDepthSolver.h

@@ -26,7 +26,7 @@ class btGjkEpaPenetrationDepthSolver : public btConvexPenetrationDepthSolver
 	public :
 
 		bool			calcPenDepth( btSimplexSolverInterface& simplexSolver,
-									  btConvexShape* pConvexA, btConvexShape* pConvexB,
+									  const btConvexShape* pConvexA, const btConvexShape* pConvexB,
 									  const btTransform& transformA, const btTransform& transformB,
 									  btVector3& v, btPoint3& wWitnessOnA, btPoint3& wWitnessOnB,
 									  class btIDebugDraw* debugDraw,btStackAlloc* stackAlloc );