added preliminary shared memory physics client/server

fix a bug in CommonMultiBodyBase: don't use data if it hasn't been allocated

examples/SharedMemory/PosixSharedMemory.h

@@ -0,0 +1,21 @@
+#ifndef POSIX_SHARED_MEMORY_H
+#define POSIX_SHARED_MEMORY_H
+
+#include "SharedMemoryInterface.h"
+
+
+
+class PosixSharedMemory : public SharedMemoryInterface
+{
+
+	struct PosixSharedMemoryInteralData* m_internalData;
+    
+public:
+    PosixSharedMemory();
+    virtual ~PosixSharedMemory();
+
+    virtual void*   allocateSharedMemory(int key, int size);
+    virtual void releaseSharedMemory(int key, int size);
+};
+
+#endif //