Modifying css regex to ignore querystrings.

Fixes issue where custom fonts can’t be rev’ed because they contain a
question mark followed by fragment identifier in the url. E.g.
`src:url("/styles/fonts/icons.eot");
	src:url("/styles/fonts/icons.eot?#iefix") format("embedded-opentype"),
		url("/styles/fonts/icons.woff") format("woff"),
		url("/styles/fonts/icons.ttf") format("truetype"),
		url("/styles/fonts/icons.svg?#icons") format("svg”);`
Merge pull request #264 from lukebussey/css-font-fix

Fixing #221 & #234 where question mark followed by fragment identifier in custom font urls prevents revving.