-> Turned lobby creation into lobby request/accept/deny exchange
--> Lobby names now must be unique

-> Added "beginGame" requests

-> Added skeleton turn-handling to lobbies
--> By default, turns are passed around in the order in which clients joined

-> Added "nag" messages. These are sent by the server when a client sends
   a message that doesn't make sense given the current game state. (for example,
   if a client asks to end their game turn, but the server knows it is not
   currently their turn)