implement pybullet.getContactPointData(), two optional object unique ids as filter

returns a pylist of contact points. Each point has the following data:

	0     int m_contactFlags;//unused for now
         1     int m_bodyUniqueIdA;
         2     int m_bodyUniqueIdB;
         3     int m_linkIndexA;
         4     int m_linkIndexB;
         5-6-7     double m_positionOnAInWS[3];//contact point location on object A, in world space coordinates
         8-9-10     double m_positionOnBInWS[3];//contact point location on object A, in world space coordinates
         11-12-13     double m_contactNormalOnBInWS[3];//the separating contact normal, pointing from object B towards object A
         14     double m_contactDistance;//negative number is penetration, positive is distance.

         15    double m_normalForce;

examples/SharedMemory/PhysicsDirect.h

@@ -21,6 +21,8 @@ protected:
 
 	bool processCamera(const struct SharedMemoryCommand& orgCommand);
 
+    bool processContactPointData(const struct SharedMemoryCommand& orgCommand);
+
     void processBodyJointInfo(int bodyUniqueId, const struct SharedMemoryStatus& serverCmd);
     
 public: