Grid and type changes

@tsmith512 

When you have a chance to review this, please let me know what you think. I'm hoping this will be a much smoother transition to Drupal.

## Key changes
* Breakpoints have been adjusted/removed/redefined based on a mobile-first approach to breakpoint design
* Removed em() function - changed $space variable and type measurement unit to pixels
* Changed footer seal to use suggest background-image SVG over inline SVG

## Still to-to
* Fix ```ul``` and ```ol``` ```list-type``` for drupals
* Refine entity bar and search for mobile


For accessibility, we may need to add `&:active`, which is what happens when you're tabbing through links on the keyboard. (Not, of course, to be confused with `&.active`, which is the current page, that you've set below.) This may be a question for @carishurd . Do we do that??