Modifying CSS RegEx to fix SVG fragment identifiers in font URIs

This is a follow to issue #264 which fixed font URIs containing question marks. This additionally fixes SVG font URIs which according to the spec must contain a fragment identifier E.g. “url("/styles/fonts/icons.svg#icons") format("svg”);”

More info: http://www.w3.org/TR/SVG11/fonts.html#FontFaceURIElement