URL rewrite errors

[Timothée Peignier]

URL rewriting in css, fail on many common case use in css like ie hack like :

url(web-font.eot?#iefix)

And SVG id in url :

url(web-font.svg#webfontIyfZbseF)

And also try to rewrite data-uri :

url(data:font/woff;charset=utf-8;base64,d09GRgABAAAAADJoAA0AAAAAR2QAAQAAAAAAAAAAAAA)

And it's a common pratice used for cross-platform web-fonts support.

[Jannis Leidel]

This is basically a dupe of #18.