Update browser support section to remove glyphicons in tables; also remove ie8 and font-face section

rems: update breadcrumbs to use new sizing; improve variables by renaming @breadcrumb-separator to @breadcrumb-divider; change up colors

- Drops all the `.make-**-column` mixins for a single set to be used
within (or outside) media queries.
- Renames `.container-fixed` to `.make-container` for consistency.
- Updates built-in grid system to use new setup.

See http://jsbin.com/qiqet/2/ for an example of it in action.