Restores Devise and ActiveAdmin in Answers::Engine

Mounts active admin in generated app
Adds to migrations for Devise and ActiveAdmin
Adds questions and tags to Active Admin dashboard
Humanize names of models in ActiveAdmin dashboard
Merge pull request #256 from 18F/fix/243_restores_admin_sync

Restores Devise and ActiveAdmin in Answers::Engine
Monkey patch Engine to copy migrations to host app

This monkey patches the rails Engine to copy the engine's
(answers-core) migration files to the host app as per:
http://pivotallabs.com/leave-your-migrations-in-your-rails-engines/
Include AATO after answers to set migration order

This causes AATO to be loaded (and its migrations) after answers-core.
It also moves all dependecies after answer-core and any other answers-*
plugins.
Remove debugging statements and unused generators
Merge pull request #250 from 18F/fix/249_copy-db-migrations-to-host-app

Copy DB migrations to host app and correctly set order.
Restoring API controllers and routes.

- adds the `Answers` namespace to API controllers
- adds RESTful routes in config/routes.rb to expose these controllers
- fixes a few small errors in the Tag and Tagging API controllers
Merge pull request #253 from 18F/fix/248_restore-api

Restoring API controllers and routes.
Dummy app skeleton + restore rake tasks (fix answers-testing dep)
Add pry-nav and fix Devise vesion errors.
Update capybara and modify rspec pattern for engines