Prevent content (footer) from flashing before template loads

This is a quick fix for the most immediate bug I found when visiting http://foundation.zurb.com/apps/docs - the footer flashes for a quick second before the content loads - very jarring.

The **real** fix involves allowing the parent `ui-view` in the docs to contain named child views like `ui-view="content"` and `ui-view="footer"`, which is possible with the way Foundation handles dynamic routes via UI-Router (I'm pretty sure), but might require a bigger effort to move some parts around in the documentation.

For now, this is a minimally viable fix that does the job.