Add support for reading remote avatar

I'm just making a pull request so I can keep track of where this is heading.
 Channels names are strings (beginning with a '&', '#', '+' or '!'
   character) of length up to fifty (50) characters.  Apart from the
   requirement that the first character is either '&', '#', '+' or '!',
   the only restriction on a channel name is that it SHALL NOT contain
   any spaces (' '), a control G (^G or ASCII 7), a comma (',').

So I guess it can.