Add more features

Add Fill region event
This works in the same way the region clear does but allows the filling of the selected region with any block

Add disable team chat
Allow the per-team chat feature to be disabled per arena

Implement queueing
If an arena is active then rather then just telling the player the arena is busy add them to a queue (per-team) so that when a slot becomes availablethey will be added as per their place in the queue