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