Always create assets in test env `rake test_app`

Build in extensions broke because Spree::Frontend and Spree::Backend are
not defined when running `rake test_app` within extension gem context

Fixes #3441
Dont require capybara helpers in core spec. Fixes #3442
Remove paperclip matchers not used in core specs.
Remove dash specs that were accidentally added during capybara 2 upgrade.
Remove unused routes. Fixes #3443
Selects 'state' as default zone type when there has not yet been a selection made.  We are already showing the 'add state' button in this case, so this commit makes the UI uniform ('state' radio is selected and 'add state' button is shown)

Fixes #3432
Only set display_name in OrderPopulator#check_stock_level when it's needed

This should speed up in_stock query checking, as it's no longer querying option_values + option_types tables as well.
Move Error Text calculation inside error block
Fixed bad style escaping within admin/products/index.html.erb

Fixes #3439
Do not check stock quantity twice when saving line item

Every time an user pressed the add to cart button spree was checking
stock in OrderPopulator and before saving the line item, through
Stock::AvailabilityValidator. I believe we only need to check stock on
the LineItem model

Fixes #3434

Conflicts:
	core/app/models/spree/order_populator.rb
Add validation of shipping_category_id to Product. Fixes #3188
README fix - use example that's still relevant
Remove select2-rails from Rails frontend gem

Bump select2-rails to ~> 3.4.1 in backend gem

Update helper `select2_search` implementation due to latest changes on
select2 generated markup, had to find a new way to grab select2 element
id

Fixes #3457
Remove rails from frontend and backend gemspecs.
Remove deface from frontend and backend gemspecs.
index spree_orders#completed_at
Add option_values to variant template [api]

Fixes #3460

Conflicts:
	api/app/views/spree/api/variants/variant.v1.rabl
	api/spec/controllers/spree/api/states_controller_spec.rb
Added :user at :tab was missing in I18N

Fixes #3455
Move font-awesome into app/assets for scss import. Fixes #3465
Fix `load_sample`

Broke after 7a5e43662c57807dafaebf8160069e4de8f1c855 which requires
product to have a shipping category

Add build for spree/sample load data task