Handle 404 responses from alerts.spreecommerce.com

Fixes #3716
Fixing backend sub-menu navigation selection by making match_path for tabs work. Tests included now.

Fixes #3683

Conflicts:
	backend/app/helpers/spree/admin/navigation_helper.rb
no longer autocomplete values in product properties fields

Fixes #3695
remove horizontalNav js from admin this extension was causing warnings on the js consoles since it was using outdated jquery functions, and hasn't been updated this js plugin was here to allow ie7 < users to see the backend navigation using full-width

Fixes #3720
fix the ActiveRecord::ReadOnlyRecord exception when the @product is null when update the variant

Fixes #3718

Conflicts:
	api/spec/controllers/spree/api/variants_controller_spec.rb
Fix syntax error.
Fix ReadOnlyError when destroying StockItem

StockMovement is a readonly object so we can't delete them. And by that
logic I believe we shouldn't clear stock items from the database either
otherwise we will have stock movements associated with non existing
stock items

Fixes #3727
Fixes #3723
Revert "fix the ActiveRecord::ReadOnlyRecord exception when the @product is null when update the variant"

This reverts commit 1e0dc2e97ffd6577178efbe3a628520c00390dd1.
Remove deprecated methods

* BaseHelper#money
* Order#price_adjustments
* Order#price_adjustment_totals
* ShippingMethod#zone
* ShippingMethod#zone=
* Product#variants_with_only_master
Bump Rails version + spree branch reference in README
Prep for 2.1 release

Conflicts:
	README.md
Bump to 2.2.0.beta
Do not generate a new identifier for a payment when it is re-saved

Fixes #3733
remove unnecessary semicolon in screen.css.scss

Fixes #3729
[backend] Move 'Taxonomies' configuration out from under 'Configuration' to 'Products' subheading
[backend] Make checks for order totals more specific in specs

Probably fixes strange build failures like: http://ci.spreecommerce.com/viewLog.html?buildId=22440&buildTypeId=bt6&tab=buildLog
Product#stock_items should return stock_items for the master variant too

Fixes #3737
Add a default format if no format is defined in the locale file. Use the same default format as the datepicker gets in the translations partial.

Fixes #3602
While an order_id field exists within inventory_units, we should be able to retrieve these using an association

Fixes #3744
Add regression test for #3744