add command-line argument for example browser and shared memory app, --shared_memory_key=<int>

fix some shared memory issues, client uses attach/detach, server uses create/remove shared memory
implement CMD_RESET_SIMULATION

examples/OpenGLWindow/GLInstancingRenderer.h

@@ -55,7 +55,7 @@ public:
 
 	void InitShaders();
 	void CleanupShaders();
-	void removeAllInstances();
+	virtual void removeAllInstances();
 
 	virtual void updateShape(int shapeIndex, const float* vertices);