change message to selected_quantity_not_available when selected quantity can not be supplied
Fetch X-Spree-Token in request.headers

As that is where it's available rather than in request.headers.env which
would bring the full header env name e.g. HTTP_X_SPREE_TOKEN

Fixes #3798
fix bug in Product#save_master (see #3746)

Fixes #3746
Fixes #3801
Allow any version of the money gem above 5.1.1

Related to #2737
remove unused credit card fields

Removes verification_value, issue_number, and start date from the
payment admin, as they aren't used anywhere within spree and were
always blank.

Adds card_type, as that may be helpful.

Fixes #3802
Remove bashisms, fix shebangs

* Remove `function`: Allows ubuntu users to `sh build.sh`
* Ensure shebangs exist on first line of scripts

Fixes #3803
Check for column_name in migration instead

Avoid a db connection when loading all Spree code right away

Fixes #3806
Use a realistic rate for the tax_rate factory
Add ability to get all of an order's adjustments easily
[backend] Improve adjustments interface

- Shows items that are adjusted and precisely how they are adjusted
- Removes date/time, since this is not really that relevant for automatic adjustments
Add short comment explaining what immutable means in Adjustment model
Ensure tax category matches when creating a new tax_adjustment from the factory

This ensures that the adjustment amount is not $0, but rather the correct amount.