A more accurate way to resolve urls

[kennethrapp]

I've noticed for a few posts the source url is blank. This shows up as a form field when submitting a link and can be changed to anything or nothing. Also, simply adding meaningless query vars to a url makes it easy to fool the matching url detection.

I think perhaps people should only have the option of changing the summary if one isn't provided, but shouldn't be able to change the source url. Also, the url matcher should be a bit better, although since some urls depend on query strings simply stripping them wouldn't work...