initial implementation to send debug lines from physics server to client,

need to add streaming because memory is too small to store all lines
initial test of PD control in physics server, need to switch to PD control for motor constraint, instead of using external forces.

examples/SharedMemory/PhysicsServer.h

@@ -1,6 +1,16 @@
 #ifndef PHYSICS_SERVER_SHARED_MEMORY_H
 #define PHYSICS_SERVER_SHARED_MEMORY_H
 
+#include "LinearMath/btVector3.h"
+
+struct SharedMemLines
+{
+	btVector3 m_from;
+	btVector3 m_to;
+	btVector3 m_color;
+};
+
+
 class PhysicsServerSharedMemory
 {
 	struct PhysicsServerInternalData* m_data;
@@ -37,7 +47,7 @@ public:
 	//to a physics client, over shared memory
 	void    physicsDebugDraw(int debugDrawFlags);
 	void    renderScene();
-	
+
 };