v0.4

Changes since v0.3:

• Added logging class for more consistent error logging
• Several classes converted to Python Dataclasses
• Switch payment/refund sync to use Finances API
• Added initial support for eBay Digital Signatures, required for the Finances API. Use the -k argument to set up a signing key.
• Updated schema to better reflect eBay API structure
• Minor bug fixes

Schema Updates:
The following updates have been made to the database, to better match the structure of the eBay API.

• sale.status -> sale.fulfillment_status (rename)
• payment_items.payment_status -> sale.payment_status (move)
• payment_items.currency -> line.currency (move)
• payment_items.item_cost -> line.item_cost (move)
• payment_items.postage_cost -> line.postage_cost (move)
• payment.last_updated (removed)
• refund.original_id -> refund.original_payment_id (move, field type changed from UNSIGNED SMALLINT(5) to VARCHAR(26)). There is no change to the data held in this field, but it will likely change in the future.

payment.processor_id now contains the eBay order id (e.g. 17-09426-91903) rather than the old integer processor ids. This is because the Finances API does not include the old-style values.