Replaced regexp lookahead with two regular expressions

[romanoff]

Idea is that I replaced
"^(?!-_(?:expression|(?:moz-)?binding))(?:[.#]?-?(?:[_a-z0-9-]+)(?:-[a-z0-9-]+)-?|-?(?:[0-9]+(?:.[0-9]*)?|.[0-9]+)(?:[a-z]{1,2}|%)?|!important|)\z/i"

regexp with:

"^(-_(?:expression|(?:moz-)?binding))/i" (it should not match)
"(?:[.#]?-?(?:[_a-z0-9-]+)(?:-[a-z0-9-]+)-?|-?(?:[0-9]+(?:.[0-9]*)?|.[0-9]+)(?:[a-z]{1,2}|%)?|!important|)\z/i" (it should match).

Probably it's good idea to look on second commit only. As first one is just "go fmt". Tests pass now.

[pomack]

Cool, I can't really look at this for a couple weeks, but will definitely want this merged. I couldn't quite understand what the regexp was doing to re-write it. The regexp was taken from the Java code.

[romanoff]

No problem. I will wait :)