Implemented support for the lobby friends/ignore list screen.

Adding/removing friends and ignores should now be supported, as well as changing online status. For testing purposes (because I don't want to make a whole bunch of new accounts), it's possible to add accounts which do not exist. This can be removed at a later date.

Currently, showing the online status of friends has not been implemented (they will always be shown as offline). It's also not yet possible to send/receive messages. I'll need to identify a few more packets before I can make this possible.