Update Stylus to 0.47.1
Update Stylus to 0.47.1

Lots of new features and several bugfixes [https://github.com/LearnBoost/stylus/blob/master/History.md](https://github.com/LearnBoost/stylus/blob/master/History.md)
gruntjs/grunt-contrib-stylus,jhenaoz/grunt-contrib-stylus