Fixes escaping for spaces

With double quotes, new lines are not consumed
Initial pass of css parsing with parslet

CSSPool has an issue parsing `[class^="ss-"]` so we're going to
try moving all parsing internal.

This parser is heavily adapted from Michael Snoyman's haskell
implementation on
https://github.com/yesodweb/css-text/blob/add139487c38b68845246449d01c13dbcebac39d/Text/CSS/Parse.hs