Started to change queue to general queue with registry of callbacks
Disconnecting client now simply removes its callback from the registry
Removed Threadpool and employed task for long running update thread of Queue
Client Manager now creates global queue
Changed queue to use spinlock
Clients connecting and disconnecting are now handled by global update queue
Registering to, unregistering from and receiving updates in the queue is now done with correct parameters.
ClientRegistry is created upon creation of Queue
Added comments
Capitalized flush method
Declared client synchronisation flush as long running thread
Merge branch 'global_updatequeue' into develop