avoid unnecessary database updates

Don't update shipment state if it didn't change
Fix order -> line_items associations

Move file to dotandbo-spree repo, line_items fixes

* Allow an admin to set a line item price or estimated shipping date
* Don't set the line_item price until checkout
Save tax_total when saving order
Add gift_message to the parameter whitelist
Don't validate stock quantity when admin editing
allow canceled orders to be credited

Allow refund for canceled orders
Avoid runtime error looking at order history for items which have since been deleted
refund deleted cards

forgot binding.pry
allow delete deleted variants from line items

prevent runtime err

more sane payment state calc
bump versions
minor performance tweaks