Refactor lobby code to remove repeated code.
Refactor lobby code to remove repeated code.

Lobbies now emit server events when players join/part them. More events
coming soon!

ShieldBattery/ShieldBattery,ShieldBattery/ShieldBattery,ShieldBattery/ShieldBattery,ShieldBattery/ShieldBattery,ShieldBattery/ShieldBattery