MxSemphore + MxThread + MxThread implementions (#80)

* Add MxSemphore + MxThread and the two implementations I could find
  of MxThread (consumers extend it and override the Run method).

* Implement a function in MxDiskStreamProvider which uses thread and
  semaphore to confirm correct layout / size of those classes.

* All 100% match except two functions with a pair of registers swapped.

LEGO1/mxsemaphore.h

@@ -0,0 +1,27 @@
+#ifndef MX_SEMAPHORE_H
+#define MX_SEMAPHORE_H
+
+#include "mxtypes.h"
+#include <windows.h>
+
+class MxSemaphore
+{
+public:
+  MxSemaphore();
+
+  // Inlined only, no offset
+  ~MxSemaphore()
+  {
+    CloseHandle(m_hSemaphore);
+  }
+
+  virtual MxResult Init(MxU32 p_initialCount, MxU32 p_maxCount);
+
+  void Wait(MxU32 p_timeoutMS);
+  void Release(MxU32 p_releaseCount);
+
+private:
+  HANDLE m_hSemaphore;
+};
+
+#endif // MX_SEMAPHORE_H