Move API docs to Rails ERB

By having Aglio generate an ERB partial, we can render the API docs from the same context as other pages in the application.

Move the route for the developer api docs to /developer since this will be the only page there.

Update the rake task to generate the _developer partial.

Add Aglio stylings to _aglio.css.scss -- these are needed to deal with the classes that Aglio expects to exist in the CSS.

A few minor nits:

- Had to revert back some of my aglio template changes due to an aglio bug. This keeps us from rounding the corners on the nav elements on the left
- If someone has a really low res desktop, the nav items on the left may not all be visible.  C'est la vie.

This should complete #246.
Oh and with your md > HTML, the HTML has to be in the same directory. That's no longer the case with ERB partials.