security-related fixes:
- Fix out of bounds read when compressing colour sequences. Found by Hanno Böck (GL#12, GL!18).
- Fix use after free condition during a race condition when waiting on channel sync during a rejoin (GL#13, GL!19).
- Fix null pointer dereference when parsing certain malformed CTCP DCC messages (GL#14, GL!20).
- Fix crash due to null pointer dereference when failing to split messages due to overlong nick or target (GL#15, GL!21).
- Fix out of bounds read when trying to skip a safe channel ID without verifying that the ID is long enough (GL#16, GL!22).
- Fix return of random memory when inet_ntop failed (#769).
9315e627ee