[api] Ensure total_quantity and display_item_total are available on orders/index and orders/show
[api] Expire taxonomies_controller#index in 3 minutes
Fix variant thumbnails not showing on frontend

The thumbnails for variant would not show on variant click. And the
product page opened without any visible thumbnails.

Fixes #3130
[api] Remove caching of products (index+show) + taxonomies (index) actions
Return Cache-Control headers for all API requests
Correct engine path.
add user_id index to spree_orders [Fixes #3186]
Remove create_inventory_units preference that is no longer used.
When adding a variant to a RMA, do not mark the inventory unit as received until the RMA has been marked as received.

[Fixes #3121]
[Fixes #3180]
[api] Skip set_expiry before_filter for states controller.

Ensure that swapping state input/select works in all contexts:

Set the default country to one without associated states so that
the spec verifies that if the selected country changes from without
associated states to one that does have them, we get the required
behaviour (the select is not hidden). Previously the spec only test
switching between two countries with associated states in teh db.

Fixes #3185
Remove Gemfile.lock within build.sh to make testing easier
only redirect to the customer details page if we are missing a billing
address [Fixes #3182]
No need to call `order.create_proposed_shipments` twice [Fixes #3181]

Shipments are already destroyed and created every time order moves from
address to delivery
Remove spree_dash until Jirafe issues are resolved
Namespace navigation tab translations so that they don't clash with translations such as en.spree.orders.show

Fixes #3133

Conflicts:
	core/CHANGELOG.md
Add changelog for Cache-Control
[API] Include per_page element in products/index responses
Rely on correct total_count in products_controller_spec
[api] variant responses now include the full description text from the product
[api] Return display_single_amount and display_total_amount in LineItems responses

This is useful if the API client wants to display a well-formatted version of the price