removes unnecessary isLoggedIn check from Application._replaceExistingLoggedInUser
adds getCurrentGames to Application
removes Bot._isLoggedIn and updates toJSON to match Player interface
gives Player an id and changes its toJSON to return the id, name and rating
sends playerId instead of id in User._getPrivateJson; sends the new
playerId with /user/logout; and removes toJSON
adds handler for /request/random_games in User - send back a random
selection of games up to the specified maximum number.