bring back private chat

working but cleanup still needed (primarily moving repeated code into
factories and making things look nicer)
bring back 'query' command
move createPrivateRoom into factory
move processMessage and hideRoom into factories
cosmetic changes

- remove link to privateChat with self
- pretiffy private chat room name (' & ' instead of '!~!')
cleanup room creation factories
cleanup room hiding and fix bug

bug: rooms were hidden for all users, not just the specific user that
hid them
remove old messageFilter

removed old messageFilter since private chat has been revived and the
logic is no longer required since the entire message storage model has
changed to allow less verbosity (see current message filter)
final cleanup
fix merge conflicts
resolve conflicts