Use an interruptible sleep to allow our threads to exit sooner

src/PlatformThreads.h

@@ -62,4 +62,5 @@ void PltRunThreadProc(void);
 #define PLT_WAIT_SUCCESS 0
 #define PLT_WAIT_INTERRUPTED 1
 
-void PltSleepMs(int ms);
+void PltSleepMs(int ms);
+void PltSleepMsInterruptible(PLT_THREAD* thread, int ms);