a few helper methods
wip: remove all snapshotting code
add metadata to vat invoice item
stripe_service#snapshot_final + specs in all cases
remove print
modify discount so that the total amount checks out
snapshot customer to invoice early on
add extra fields to invoice (from stripe metadata), wire up final snapshot
extra invoice model methods to check if there's vat/discount
bugfix: correct subtotal_after_discount when vat and no discount
fix cassettes
failing spec discount rounding
reimplement discount calculation with formula
Merge pull request #67 from piesync/discounts

Discounts + VAT