Added flags clear for thread and new constructor for queue.

include/sta/rtos/queue.hpp

@@ -34,6 +34,11 @@ namespace sta
 		 */
 		RtosQueue(osMessageQueueId_t handle);
 
+		/**
+		 * @param length The maximum number of elements to be stored in the queue.
+		 */
+		RtosQueue(uint32_t length);
+
 		/**
 		 * @brief Place message in queue.
 		 *