Fix on_hand behavior to be compatible with changes in Spree master

Fixes #64
Dont automatically assign admin role.

Please assign admin role manually now:

user = User.find(...)
user.spree_roles << Spree::Role.find_by_name("admin")

Fixes #66
Use correct calculator within checkout_spec (shipping, rather than generic)
It's not necessary to create a variant for checkout_spec tests
Add User#admin? method.

Fixes #67
Fix require for BarAbility in Admin::UsersController spec
Correct shipping method used in promotion adjustment spec
Manually assign admin role within promotion_adjustment_spec tests

This is due to f5c812a09661925afe8f22cf81d3d17ad5836764
No need for test for Admin::OrdersController#show permissions any more

This was removed as part of the shipments changes on spree/spree master
Gitignore.

Extended ignore list.
Add method to rake task.

Add method to rebuild migrations.
Updated date in license.
Refactor cleaner migrations.
Yaml lint locales.

Now locales are in alphabetical order so its more esy to see
inconsistency.
Cleanup views.
Format overrides.

Make overrided more readable.
Refactor controllers etc.
Refactor specs.
Refactor gemspec and engine.

- Cleanup.
- Add VERSION file.
- Fuubar nice for long running specs.
- Swaped summary and description.
- Moved dev gems into gemspec.
- Bumped RSpec to 2.13
- Bumped shoulda-matchers to 1.5.2
- Explicit spree dependencies.
Updated Versionfile.