Bug 842858 - styleguide updates

* Expanded FxOS branding page
* Added FxOS color page
* Added color values to Firefox and Mozilla color pages
* Misc copy updates in communications

FxOS promo materials page still pending, commented out for now but this commit includes the partial page
Merge pull request #657 from craigcook/bug-842858-styleguide-updates

Bug 842858 - styleguide updates