Getting ready for Teatro.io stage server
Remove extra " in banner comment

Might have been leftover from when the banner was a simple double-quoted string.

Closes #5093
Make tracking number in admin order view a clickable link, pointing to shipper's tracking website

Closes #5094
Add postal code validation using the Twitter Cldr gem

Closes #5079
Fix Spree::Promotion not applying all of the time.

There was a specific case in which promotions added to an order would
not apply to new items added to the cart. This corrects that by having
the PromotionHandler activate all promotions already associated with the
order as well as any with a blank code and path.

Closes #5072
Adds 'current order' API endpoint

This enables an API client to load a user's latest order. At Bonobos, we
use this to load the user's last active cart.

The find_current_order method is broken out to a separate method to
enable gems like spree-multi-store to customize its behavior.

Closes #5069
Remove unused method
Merge pull request #5099 from xjunior/patch-1

Remove unused method
Reimbursements model & Manual intervention resolution for Returns

- New Reimbursement model which encapsulates the concept of reimbursing a set of accepted return items, which will be reimbursed via one or more reimbursement methods (e.g., refunds, exchanges, store credits, etc)
- Moved refund logic from customer return into Reimbursement
- Ability to resolve "manual_intervention_required" returns items in the Admin UI
- Provide preview of how reimbursements will be parceled out before performing them
- Add a default "ReimbursementPerformer" that figures out how to distribute a reimbursement

Other enhancements/fixes:

- Suggested amounts now update on input changes
- Add generic "success/notice/error" state colors
- New Admin show page for customer returns
- Remove customer return refund endpoint
- new Admin ReimbursementsController & ReturnItemsController

Created by @richardnuno & @jordan-brough

Fixes #5098
Fix broken spec.
Merge pull request #5067 from semenyukdmitriy/teatro_stage

Getting ready for Teatro.io stage server
Validate uniqueness of order numbers... Why was this FIXME never fixed until now... Fixes #5102
Add `Spree::Promotion#products` back.

Currently used in the frontend.

Closes #5071
Add mail_from_address field to general settings page

Closes #5047
changed generate_order_number method for insure that generated numbers never finish #5102
Fix broken specs from order number refactoring, and improve performance. Fixes #5102
Fix payment state in order importer. Fixes #5109
Allow assigning source_id and source_type rather than creating a new source.

Conflicts:
	core/lib/spree/permitted_attributes.rb
Revert "Allow assigning source_id and source_type rather than creating a new source."

This reverts commit 70de4094d3d5e53d35c52f8eb25b630429481cbd.
Use rand(10) to cover all digits 0-9. Fixes #5113