More updates to in-memory orders handling.
Allows proper volume discount calculation for fake orders that are
not to be persisted.
Fix discount calculation for non-persisted orders.
Add force_volume_volume_discount_update method.
Don't refresh line_items with unsaved changes.
Update the documentation.
Allow volume as sum of product's variants.
Bump version for recent fixes.
Alias line_item.total to amount_with_volume_discount
Fix: don't update line_item discount unnecessarily
Display "next at" instead of "next 1 at".
Add link to screenshots from readme.
Add progressive volume discount strategy.
Don't show volume prices marked for destruction.
Instead of changing price subtract discount from order total.
This is a first step to allow us to apply discount differently to quantity
portions of the same variant. I.e. sell 3 first units for $10, the next three
for $9 and all the next for $8.
Fix a bug for vanilla 0.40.4 spree.
There is a pull request waiting for spree/master to pass this argument, but as
for now it's not supported on neither 0.40 or edge spree.
List master variant volume prices in the cart form
Copy master volume prices to new variants.
Copy master volume prices when cloning product.
Update line items prices when user logs in.
Add authors note to readme.
Add readme note about volume customers.