Add Product#total_on_hand convenience method.
Default to spree_auth_devise 2-0-stable branch for extensions generated by Spree 2.0.x. [Fixes #3242]
Remove Rails t() override method

Rails t() offers a couple more nice features before calling I18n.t()
see http://api.rubyonrails.org/classes/ActionView/Helpers/TranslationHelper.html#method-i-translate

And since right now we can't make Spree.t() behave the same way as Rails
t() helper we'd better let users choose t() default, in cases Spree.t()
can't cover, without throwing warnings

Fixes #3176

Fixes #3256
Explicitly declare manifest partial location so the shipment partial can be rendered in templates outside the orders folder.
Log CVV response messages on payments

Fixes #3266