We should support the standard syntax of host[:port] in tlclient. The current
way of changing port is cumbersome to say the least and you easily forget that
you've set it to something odd.
See thread in komintern starting with article 290573.
Make sure this doesn't introduce new IPv6 bugs, the code needs to handle host:port strings such as [2a00:801:107:4700:92b1:1cff:fea0:ca58]:22