replace PlayerDeathEvent with EntityDamageByEntityEvent
spectators shouldn't pick up items
successfully clears players before world deletion
Merge remote-tracking branch 'eric/freezeFix' into game-end
Merge branch 'game-end'
major refactor of GameManager and GameSettings
ensure all broadcasts get all players
alter end timer conditions; get default world
Unregister GameManager Listener on world destroy.
reset player on end of game
Merge branch 'GameManager-refactor' into deallocateListeners

Conflicts:
	src/main/java/net/SimpleSurvival/GameManager.java
Move unregister to end of process.
Fix double enum.
make listeners world aware
fix the 'everybody dies' glitch
fix the multiplayer invincibility glitch
fix no world end glitch
player visibility fix
change world return location
change player damage conditions