Auditorium mode+svstag+akill+rakill fixes

- Auditorium mode fixes (cmode +A): Hide quits and nick changes as well.
- Changed SVSTAG to send/receive umodes in text and fixed incorrect and
  missing comments.
- Changed m_akill() to warn about bogus akills and also "fix" them (add them
  anyway for 30 minutes as services only sends AKILL commands when it really
  wants to take out users).
- Added more debugging to m_rakill().

-Kobi.