Rename mobile to theme-default, remove view-based media query, and load theme-default in theme to close #152.

For now, theme-default just wraps the previous mobile stylesheet in a media query to preserve functionality for further refactoring via issue #88 and loads theme-default as part of the asset pipeline, rather than via a specific custom helper.
Remove custom mobile stylesheet picking class that is made obsolete by adding media queries to theme-default as part of #88
Remove obsolete print stylesheet
Remove 'Display for ...' links in footer.
Remove obsolete specs for mobile_stylesheet_media, which was removed
Fix mobile project title positioning

This was broken by my earlier webfont change
Require theme-default after layout.scss

In its current form, our theme-default.scss styles still depend on their
ability to override things set by the desktop styles.