Extract regexes for modules
Extract regexes for modules

@trotzig recently brought up the idea of using the regexes that I wrote
for determining uniqueness for another purpose: finding imports. I like
this idea, so I'm taking the first step of extracting these regexes for
general use. Since this makes the normalize method so small, I decided
to inline it back to its original location.

trotzig/import-js,Galooshi/import-js,lencioni/import-js,trotzig/import-js,trotzig/import-js,lencioni/import-js,lencioni/import-js