Validate Application Scopes

- add validation to Doorkeeper::Application to ensure that its applications match those in the configuration
- add factories for Doorkeeper::Application and User (this is WIP)
Remove comments from User Factory and API Spec
Merge pull request #200 from 18F/feature/validate_application_scopes

Validate Application Scopes
Merge remote-tracking branch 'origin/devel' into feature/travis
create shippable.yml, add back simple-cov