Support prefixing URLs
Add .rev. to the filename when revving
Tweak so extensions like .appcache aren't ignored (not within 2-4 char limit)
Merge pull request #12 from austinhallock/master

Tweak so extensions with > 4 chars like .appcache aren't ignored
readme for prefix option.
Merge commit '2880d7c8bd79e10d05233910dc4bba1466a7edf6'
Merge commit 'fa5a22a245802993c8808113981e114ddd522d23'
Tweak documentation
Version bump + small documentation correction
Try and fix formatting issue
Support arbitrary URL transformations
Support @ symbol in image paths
Version bump + code style corrections + small documentation change + fix unit test name