Allow latest versions of compass-rails and sass-rails

Fixes issues with apps using Rails 4.1 and compass image spriting
Using sass-rails 5.0.beta while building.
Merge pull request #648 from magiclabs/fix/sass-dependencies

Allow latest versions of compass-rails and sass-rails
Change the references to jquery ui to match new directory structure.

This adds the capability to be compatible for the jquery-ui-rails 5.0.0
gem.
Merge branch 'jquery-ui-rails_upgrade'
Merge branch 'master' into feature/json-api-namespace