Identifiers may now begin with "--".
Identifiers may now begin with "--".

See bullet point two of: http://dev.w3.org/csswg/css-syntax/#changes-CR-20140220

tempbottle/rust-cssparser,tempbottle/rust-cssparser,frewsxcv/rust-cssparser,notriddle/rust-cssparser,servo/rust-cssparser,SimonSapin/tinycss2,notriddle/rust-cssparser,frewsxcv/rust-cssparser,disjukr/rust-cssparser,servo/rust-cssparser,disjukr/rust-cssparser