Associate contributions with the payment processor used to make it

Display Payment Processor name next to Payment Instrument on View Contribution page if present in related financial transaction.

— Original Post ----
When using multiple payment gateways for credit card donations, it is difficult to tell which payment gateway was used when viewing a contact's contributions tab. It simply says "credit card" in all cases. It would be nice if the payment processor name was included, too, like "credit card (PayPal)".

Thoughts on this? From my best guess, it would require:

• adding a payment_processor_id column to the civicrm_contribution table
• adjusting contribution DAOs/BAOs to fetch that column
• save payment processor id when creating contributions, if a payment processor was actually used
• render payment processor name when rendering contribution details
• update docs