Added traceTASK_SWITCHED_OUT macro.

Source/include/FreeRTOS.h

@@ -180,6 +180,12 @@
 	#define traceTASK_SWITCHED_IN()
 #endif
 
+#ifndef traceTASK_SWITCHED_OUT
+	/* Called before a task has been selected to run.  pxCurrentTCB holds a pointer
+	to the task control block of the task being switched out. */
+	#define traceTASK_SWITCHED_OUT()
+#endif
+
 #ifndef traceBLOCKING_ON_QUEUE_RECEIVE
 	/* Task is about to block because it cannot read from a 
 	queue/mutex/semaphore.  pxQueue is a pointer to the queue/mutex/semaphore