Update to grids, widths, and ups + minor changes to example site.

This update adds more configurable variables in these partials.

GRIDS: spacing around grids

WIDTHS and UPS: how many classes do you want available at specific breakpoints.

The classes in widths and ups were hard-coded, they've been replaced with mixins to generate the classes based on config values.

Also
* removes the google font, which slows down the site when offline
* updates grids page with new examples
* adds an IE support disclaimer to home page