Remove backwards-compatibility from SassRule.
Remove backwards-compatibility from SassRule.

Kronuz/pyScss,cpfair/pyScss,Kronuz/pyScss,hashamali/pyScss,cpfair/pyScss,Kronuz/pyScss,cpfair/pyScss,Kronuz/pyScss,hashamali/pyScss,hashamali/pyScss