Store credit reimbursement type
Add migration for Store Credit Reimbursement Type. Update readme for returns and exchanges integration info
Set the currency on store credit when creating reimbursement credits
Validate presence of currency on store credit
Cancellation of credits
Before destroying store credit, check amount used
Remove line item presence validation Gift Card. We are going to start selling physical gift cards outside the realm of the online store, which will not require a line item (for the confirmation email/order history page)
Revert "Remove line item presence validation Gift Card. We are going to start selling physical gift cards outside the realm of the online store, which will not require a line item (for the confirmation email/order history page)"

This reverts commit dd157939f9e26fbd05f829ef8e2029f6e35969a2.
Payment_state check was preventing store credit from being refunded

Currently matches credit card can_credit? logic
Fix issues caused by float imprecision

Because, e.g., 8.21.to_d != 8.21

This was causing `validate_authorization` to fail for certain numbers because it didn't think enough funds were available.
Fix admin controller page title

It turns out the "store_credits" key is a special value that
Spree::Admin::BaseController uses to set the page title. Our setting it
to a tree of other messages led to this pretty title:

Spree Administration: {:credit=>"Credit", :authorized=>"Authorized", :captured=>"Used", :allocated=>"Added", :errors=>{:unable_to_fund=>"Unable to pay for order using store credits"}}

Use a non-special key instead, and the title magically becomes "Spree
Administration: Store Credits"
Don't create gift cards until the order has been completed
Round down reimbursement
Display gift card redemption codes in admin order view
Move create creditable to module eval on reimbursement helpers
Allow admins to redeem gift cards for users
Allow store credit to be amended down to the amount used even after partial usage
Send an email for each gift card purchased
Merge remote-tracking branch 'refs/remotes/athal7/for-merge'

Conflicts:
	app/models/spree/order_decorator.rb
	spec/models/spree/order_decorator_spec.rb