Removed width and such on .page-box
Basic responsiveness(apps#index)

So this gets us a decent-looking layout on smaller and tiny
screens, although there's two weak points to consider:
- The new respond-to mixin uses ems instead of rems, tragically
- This whole thing would be easier if I didn't have explicit
  widths/height involved in the app listings
apps#new responsiveness
apps#show responsiveness swag
apps#confirmation responsiveness
Merge pull request #22 from csampson/mobile

UI Responsiveness