Added helpful tab placeholder
Added onmode to handle receiving mode updates

- the real Interloper wanted his or her name back
- fixed outgoing /me
- on404 doesn't try to delete last message anymore.
- added /whois, even though it wont handle the response.
Added tab completion for channels

- Fixed server sources being parsed incorrectly
- Fixed /query from sometimes acting as /join
- Hadn't actually tested /whois... fixed obvious protocol error.