Revert memory leak commits

5f7001e: "Added a new branch"
01456ed: "Fixed a lot of memory leaks"
dac4493: "Fixed all remaining memory leaks that I could figure out"
0792db7: "Removed the smnew macro and the call to _CrtSetDbgFlag()"

Some of these caused destructor-time problems due to static initialization
order fiasco and related issues.  Notably, the program would no longer exit on
OSX and had to be killed.

There were probably legitimate fixes in here, but since these are monolithic
commits it's too much work to extract them now.  Let's reapply them
individually and in the forward direction.

src/RageThreads.cpp

@@ -138,8 +138,8 @@ struct ThreadSlot *g_pUnknownThreadSlot = NULL;
  * so possibly racing over them is harmless (simply using a stale thread ID, etc). */
 static RageMutex &GetThreadSlotsLock()
 {
-	static RageMutex lock( "ThreadSlots" );
-	return lock;
+	static RageMutex *pLock = new RageMutex( "ThreadSlots" );
+	return *pLock;
 }
 
 static int FindEmptyThreadSlot()