Adding dependency directives to stylesheet to avoid DependecyError

This is actually a follow up of issue https://github.com/comfy/comfortable-mexican-sofa/issues/397. 

Please comment if there is a more efficient way of doing this.

The following pull request from the sprockets-rails gem
(https://github.com/rails/sprockets-rails/pull/96) requires that the
referenced assets be declared explicitly with the dependency directives
(i.e. the `depend_on` or `depend_on_asset` directive).

Adding the dependency directives to the affected stylesheets.