Finally gets rid of the redundancy when checking if a record has been beaten
Adds tab-completions for arenas and properties to the edit command
Adds an ArenaEditableProperty enum to keep track of editable arena properties
Removes some finished TODOs
Registers all listeners
Registers all commands
Adds more descriptive TODO comments to each command
Removes unintended double storage of dropper arena sessions in DropperArenaHandler
