Highlight CSS media queries

[NV]

CodeMirror's CSS parser does not support CSS3 Media Queries.

@media screen {
  body {font-family: sans-serif}
}

Rules inside @media screen {} do not highlighted properly.

[marijnh]

Thanks for the report. I pushed a fix 0fac80d

[marijnh]

This was actually fixed wrongly the first time -- new commit at 57cf34e