Fix truncated KILL text event, adjust placement of notices in automatic mode, and adjust handling of notices to prefix-channels

The truncated KILL message is literally ancient history.  It is older than hexchat itself.  In 2016, it will be old enough to drive to a gas station and buy a pack of cigarettes.

The handling of notices was, quite frankly, bogotic.  Never before have I had a client try so hard to hide from me information which I was probably looking for.  Whose idea was that anyway.

The prefix-mode notice change is self explanatory.