Fix split_prices_from_variants rollback migration

- Change scale and precision
- Fix data migration
- Add `:null => false` to `spree_variants`

Fixes #2358
Use localized error message for email validator

Fixes #2364
Optimised images

Fixes #2349
fix inline javascript for address state elements

Fixes #2357
Fix - Shipment includes vat is allways false after save

Fixes #2368
Fix The action 'show' could not be found for Spree::Admin::TaxSettingsController

Fixes #2368
Improves promotion#products collection method

promotion#products should return products from all rules that respond to
a products method and not just from the built in PromotionRule::Product
class.

This should make it easier for developers to use their custom rules to
interact with Spree::Promotion

Fixes #2363
move gateway form required chars "*"

close to their labels to uniform with the rest of forms

Fixes #2362
Fixed issue with duplicate thumbnails on ProductController#show

Fixes #2361
Remove debug from -v/--version call