Merge branch '2-1-lav' into 2-2-lav-experimental

Feature specs are still failing, largely due to overrides that dont
apply properly anymore or missing translations. The rest of the specs
pass.

One notable change is that the originator association on Adjustments
have been renamed to source.

Conflicts:
	Gemfile
	app/assets/javascripts/store/spree_gift_card.js
	app/assets/stylesheets/admin/spree_gift_card.css
	app/assets/stylesheets/store/spree_gift_card.css
	app/controllers/spree/checkout_controller_decorator.rb
	app/controllers/spree/orders_controller_decorator.rb
	app/controllers/spree/store_controller_decorator.rb
	app/models/spree/adjustment_decorator.rb
	app/models/spree/calculator/gift_card.rb
	app/models/spree/gift_card.rb
	spec/models/spree/calculator/gift_card_spec.rb
	spree_gift_card.gemspec