Okay, TIL that properly matching URLs with a regex is really f'ing hard.  Like, [this regex](http://stackoverflow.com/questions/161738/what-is-the-best-regular-expression-to-check-if-a-string-is-a-valid-url) hard.  Plus, most "bugs" in linkify are really just URLs being a pain in the ass to match via regex.  I'm just going to use linkify.