Threads vs. Queues lifetimes, cleanups.

- Ideally Queues must outlive the threads using them, but wasn't done so. Yes, std::shared_ptr them!
- Now queues are always valid in the context of the threads using them.
- No longer need tedious queues deallocation by the original owner.
- Misc cleanups.

src/util/ThreadBlockingQueue.h

@@ -25,6 +25,8 @@
 class ThreadQueueBase {
 };
 
+typedef std::shared_ptr<ThreadQueueBase> ThreadQueueBasePtr;
+
 /** A thread-safe asynchronous blocking queue */
 template<typename T>
 class ThreadBlockingQueue : public ThreadQueueBase {