Fixed the PING responder and added a couple of commands
Data dropped in the parser mailbox is no longer in a singleton list
it is just data - but the PING pattern matcher hadn't been update
with this chage.

I added a NICK command, and a PART command `#n` and `#p`
respectively

Also made it so that there should be a space after commands which
take an arguement, it's a little naive at the moment though.