Fix URL matching regex
Fix URL matching regex

The URL matching regex as currently used by dust is too liberal, and will just
match about anything.

Some examples:

  "establishing connection..." => connection...
  "setting volume to [50%]" => 50%]

The following expression is an adapted copy of urxvt's URL matcher.

travisred/dunst,travisred/dunst,thomasf/dunst,LukeShu/dunst,thomasf/dunst,LukeShu/dunst,LukeShu/dunst