fix some warnings, add some doc

libs/main/thread/piblockingqueue.h

@@ -87,6 +87,7 @@ public:
 	 * exceeding the queue's capacity, returning true upon success and false if this queue is full.
 	 *
 	 * @param v the element to add
+	 * @param timeoutMs the timeout waiting for inserting if que is full, if timeout = 0, then returns immediately
 	 * @return true if the element was added to this queue, else false
 	 */
 	bool offer(const T & v, int timeoutMs = 0) {