Prevent Duplicate Character/Player Names

Prevents creation of multiple characters with the same name, or a character with the same name as a player, or a player with the same name as a character. Player may make a character with its own name, however. This only affects charcreate and the unloggedincommand 'create', so puppets would be fine.

I THINK this is desired and expected behavior. Multiple players being able to charcreate characters with the same name seems like it should lead to a confusion state. Creating a new player who happens to have the same name as an existing character would seem to be just as confusing.