introduce unreg_privmsg_func, fix minor autoinvite issue, alter account-finding on...

introduce unreg_privmsg_func, fix minor autoinvite issue, alter account-finding on local services clients

* introduce unreg_privmsg_func: unreg_privmsg_func()/unreg_notice_func() - both of which reverse the effect of reg_privmsg_func()/reg_notice_func()

* fix minor autoinvite issue: UserAutoInvite (aka: '!uset autoinvite ..') no longer invites you to channels you weren't in if the server you are on just reconnected to the network

* alter account-finding on local services clients: non +k users on the local services server are now no longer referred to as services (at least not in regard to accounts..)

git-archimport-id: srvx@srvx.net--2004-srvx/srvx--devo--1.3--patch-57