Account for minified values in border-radius

Most rules stop matching at semi-colon or closing brace (";}"),
but border-radius only looked for closing brace. This caused
minified input like:

    .foo{border-radius:1px 2px 3px 4px}

To be converted to invalid CSS:

    .foo{border-radius:2px 1px 4px} 3px

Also preserve trailing whitespace.