Fixes for IE specific syntax

BUG=

Review URL: https://chromiumcodereview.appspot.com//13474004
Merge branch 'master' of https://github.com/dart-lang/csslib into var_work
bump csslib version

BUG=

Review URL: https://chromiumcodereview.appspot.com//13641002
Merge branch 'master' of https://github.com/dart-lang/csslib into var_work
Integrated CR comments and more cleanup