Implemented API changes.
Added logging messages when registering a game.
Don't send join message if it is null.
Fixed index of game in list command being off by one when displayed to a player.
#loadActiveSign(File) returns a boolean now.
Fixed the #registerVariable(SignVariable) method.
Added shortNames for sign types for easy reference.
Implemented API methods.
Added a method to retrieve signs types based on their short names.
Added a method to retrieve a read-only collection of registered sign types.
Added a method to create an active sign.