Create a PhysicsLoopBack that includes both PhysicsClient and PhysicsServer over shared memory.

Add a test for PhysicsLoopBack.

examples/SharedMemory/PhysicsLoopBackC_Api.cpp

@@ -0,0 +1,15 @@
+#include "PhysicsLoopBackC_API.h"
+
+#include "PhysicsLoopBack.h"
+
+
+
+//think more about naming. The b3ConnectPhysicsLoopback
+b3PhysicsClientHandle b3ConnectPhysicsLoopback(int key)
+{
+	PhysicsLoopBack* loopBack = new PhysicsLoopBack();
+	loopBack->setSharedMemoryKey(key);
+	bool connected = loopBack->connect();
+	return (b3PhysicsClientHandle  )loopBack;
+}
+