Include a new grid system (raster.gs)

This branch includes a flexible, standalone grid system into bootstrap. You can see the documentation up here: http://www.raster.gs .

The defaults are set to match the current grid of twitter bootstrap so there is no confusion. Raster.gs enables you to create more grids, change the names of the grid classes and even change the number and/or widths of each column. You can also nest your grids inside of your mediaqueries.

I think there are few people who only install bootstrap because they want to use its grid. Therefor they also need to include dependencies like mixins and variables. These dependencies are not needed when using Raster.gs.

I didn't know a good way of importing the .scss-files into bootstrap while keeping it in the bower_components folder.