Don't send WHO for queries.

Also, 8922668 sends a MODE, producing the following:

22/04/13 01:47:02,083 Textual[74434]: -[IRCClient sendLine:] [Line 947]: << WHO #cherokee
22/04/13 01:47:02,083 Textual[74434]: -[IRCClient sendLine:] [Line 947]: << WHO Vito
[...]
22/04/13 01:47:16,214 Textual[74434]: -[IRCClient sendLine:] [Line 947]: << MODE Vito
22/04/13 01:47:18,160 Textual[74434]: -[IRCClient ircConnectionDidReceive:] [Line 2879]: >> :calvino.freenode.net 502 anaconda :Can't change mode for other users
Merge pull request #376 from anaconda/patch-1

Don't send WHO for queries