Check if payment is required before checking if there are any payments in ensure_valid_state
Deleted shipping methods are now accessible from a shipping rate

Fixes #3829
Add exceptions for blank records in tax categories migration

Fixes #4204
Added Regexp tab matching
Catch exceptions within Spree::Stock::Estimator#shipping_methods and log them

Fixes #4227
Import variables using full-path, so that an overridden file in the application will be loaded

Fixes #3415
Show advice to run bundle exec rake test_app if dummy/config/environment fails to load
Added missing index for variant_id and currency on spree_prices

Fixes #4232
Remove Order payments association's inverse_of

This was causing spree/spree_gateway#132, and would've caused similar issues for all non-token gateways (i.e. gateways that send CC info rather than getting a token and using that instead)

Super incredibly glad that we found this out before master was released as a real gem.
Fix alert styles

[Fixes #4238]
[api] Handle adding option types to an existing product
[api] Allow creation of variants on an existing product
[api] Allow existing variants to updated
Make key access consistently symbols

Fixes #4254
Versionfile is deprecated

We need to figure another way (or another file, same file?) to boot the
dummy app properly when or if needed
Create Spree::Migrations to warn about missing migrations

Everytime users boot their apps they would see a warning like:

    [spree] Missing migrations. Run `bundle exec rake railties:install:migrations` to get them.

Fixes #4080
Simplify OrderPopulator

OrderPopulator was previously taking multiple products at once. It doesn't need to do that, given that the only place it's used (OrdersController#populate) only ever passed in a single variant id and quantity.
Remove Order payments association's inverse_of

This was causing spree/spree_gateway#132, and would've caused similar issues for all non-token gateways (i.e. gateways that send CC info rather than getting a token and using that instead)

Super incredibly glad that we found this out before master was released as a real gem.
Use pure delegate in Spree::Gateway, compared with delegate_belongs_to

The provider method here is not a belongs_to association, so there's no good reason why we should be using delegate_belongs_to at all. Further more, delegate_belongs_to defines setters for these methods, but that is not necessary at all since these methods do not have setters!
Improved tracking URL generation to handle spaces in tracking numbers

Fixes #4233