Updating the footer for edx.org and open edx.

Making the footer look more like the front page.

* Updated SASS for footer
* Updated HTML for open edx and edx.org templates
* Updated stubbed views
* Added !important SASS to overwrite some blanket LMS styles

Updating steve.m.sandbox.edx.org to have the latest changes.
@wedaly @andywaldrop @dianakhuang @griffresch 

I don't think we should have hardcoded links to our Twitter, FB, etc, in any template.  I believe we already have some setting for marketing links that handle this; try seeing how we link to twitter elsewhere in the platform iirc