Expose pushProfileTimer / pop ProfileTimer in PhysicsClient API to benchmark Python parts of PyBullet.

reduce 'm_cooldownTime' from 1000 microseconds to 100 microseconds (overhead in raycast is too large)
If needed, we can expose this cooldown time.
Replace malloc by btAlignedObjectArray (going through Bullet's memory allocator)

examples/SharedMemory/PhysicsClientSharedMemory.h

@@ -89,6 +89,8 @@ public:
     virtual int getNumUserData(int bodyUniqueId, int linkIndex) const;
     virtual void getUserDataInfo(int bodyUniqueId, int linkIndex, int userDataIndex, const char **keyOut, int *userDataIdOut) const;
 
+	virtual void pushProfileTiming(const char* timingName);
+	virtual void popProfileTiming();
 };
 
 #endif  // BT_PHYSICS_CLIENT_API_H