Add field for attachment_url preference to image settings page

Fixes #2344

Conflicts:

	core/app/views/spree/admin/image_settings/edit.html.erb
Remove commented out lines from payment factory
Bump ActiveMerchant dependency.

Fixes #2346
Depend on Ransack 0.7.2

This is due to ernie/ransack#176.
Use localized error message for email validator

Fixes #2364
Fixed issue with duplicate thumbnails on ProductController#show

Fixes #2361
Updated paperclip rake command with proper class info for spree.

Fixes #2369
Correct Taxon class reference in taxon.rake

Fixes #2370
Make admin/orders/shipments_spec.rb not dependent on a checkbox's id
Auto-orient uploaded images based on EXIF data

Fixes #2338
Remove auth-specific translations from core

These should live in the auth extensions
Use 1.8 hash syntax within API::V1::BaseController