Adds a test for inlining content with protocol-less URLs.
Adds a test for inlining content with protocol-less URLs.

This refers to #632, but just confirms we do the right thing.

GerHobbelt/clean-css,MartyIX/clean-css,stuht/clean-css,island205/clean-css,scottgonzalez/clean-css,jakubpawlowicz/clean-css