Supporting server commands as / commands

[osa1]

micr0 reported this on IRC. We currently don't have / commands for server commands like WHOIS. The idea is that you can always send commands directly to a server by sending it in the server's tab. However tab completion doesn't work in the server tab, so if you have a long and weird nick in a channel and want to do WHOIS you can't do /whois ab<tab>, and in the server tab WHOISE ab<tab> won't work. You have to copy the nick and paste it in the server tab.

If we supported /whois then /whois ab<tab> would complete the nick in the channel tab.