run spamfilters against NICK

[jesopo]

this isn't perfect because it'll format as

0:nick1!user@host#0 NICK :nick2

(note the :) so maybe I should beat up match_message's snprintf a bit

[dwfreed]

This should also apply to the initial nick, otherwise one could still register with the bad nick. Alarm consumers would need to handle that situation, though.

[jesopo]

this is my initial solution for how alarm consumers are going to handle this case: slightly different snote. bikeshed on the format please

[jesopo]

we can't make people immune from this by them being an oper, obviously, and this is the only alternative that came to mind

[jesopo]

or maybe we just treat it like a RESV. you have to connect first and then switch your nick

[jesopo]

i plan to do a second PR after this that runs spamfilters against USER; when i do this im going to move away from using match_message(...) for everything and refactor out the bits of match_message(...) that are useful for things that are not messages, but i thought i'd keep this simple to start with.