Try to track account and send client a 900 when appropriate

Fixes #4, causes an issue found by bd where Kiwi doesn't do EXTJWT properly until it sees a 900. This isn't tested yet and is missing bits but is along the lines of what should resolve the issue.

Main changes:

Adds the account row to the connections table on the main db.
RPL_LOGGEDIN (900) will now be sent to newly-connected clients as part of the welcome burst if upstream is logged into an account.
CAP is now negotiated properly. It used to detect CAP continuation lines by seeing if param 0 is *, but param 0 is always that. Param 2 is * if the line's a continuation line, so changed over both instances of this.

kiwiirc / kiwibnc

Try to track account and send client a 900 when appropriate #5