Mobile changes

Change nav on extra small devices.
Mobile size fixes.

Changed type, padding, and margin sizes for the mobile and small media
queries.
Merge branch 'rm-changes'
Center footer on mobile. Mobile Bug fixes.

Centered footer on mobile and small media queries.

Fixed a bug that caused navigation to rearrange at 601px wide.

Added padding to last child of colophon to give it some breathing room
on mobile.
Merge branch 'rm-changes'