Update views to use Bootswatch Yeti Theme

Button sizes changed to small, top padding changed to fit Yeti's navbar
default height, and bootstrap.css, jquery.js, and bootstrap.js have been
added manually - this will not be done using grunt wiredep.
Refactor API calls into a service and change api route

To keep API logic out of the controller, Restangular calls moved to a
service. The API route is now also prepended with /api/ just to keep
things clear with routes.
Hook up sidebar to update main editor

Clicking 'edit' on a question will update the main editor view by use of
an observer.
Add dummy button to export to XML

Literally a dummy button to help get an idea of how things may work.
Refactor Sinatra structure and add tests

Clean up the application structure a bit and add a few tests to the API.
Still need to implement test for deletion.
Update Vagrantfile

Update port forwarding for default rackup and disable port forwarding
for livereload.