Makes semantic.gs work with the latest stylus

[eugeneware]

The grid.styl file was quite broken in the current release. It also didn't generate the same CSS as the less examples, and didn't support push and pull.

I've updated grid.styl to work properly, support push and pull, generate the same CSS as less, and also provided example stylus sheets for all the standard examples.

[scottwhitworth]

Thanks for the fix... working great!

[Delapouite]

Great. Thanks for this fixes Eugene.

[csmosx]

+1 I probably should've checked the pull requests before fixing all the same things.

[aredridel]

+1!

[sergeevabc]

@nharbour, thank you!
I hope your commits will be merged someday.

[nijikokun]

I've added in support for omega (see neat.burboun.io for more information as to how useful it is, sidebars etc):

https://gist.github.com/Nijikokun/6144380

Also, lots of issues if you don't use brackets on column and I couldn't figure out how to do row, added columns support to push and pull as well.

[abhoopathy]

@eugeneware, thanks for doing this! I've used it on a couple projects so far.

One thing I noted was I had to rename the 'push' mixin. Stylus has a native push method, which is used by nib to generate vendor prefixes:
https://github.com/visionmedia/nib/blob/master/lib/nib/vendor.styl#L147
http://learnboost.github.io/stylus/docs/bifs.html