fix a memory leak due to persisting player events & socket channels. fixes early alt limiting.

Conker addressed several issues that would cause Player objects to persist in memory. Fixes memory leak & early alt limiting.

for Conker: I changed the Players.java hash method to use uuid instead of username hash, in case Player object & Player cast as a Mob enter the same hash map, then they will hash the same. Players.java uuid is based on username hash anyway. Otherwise i just tested & removed comments about how you were worried it might not be strictly correct in some places.