As a developer myself, I'd love a plugin API in aquamail so I could add my own features to it. A general plugin inteface would be awesome, but I'd be happy to start out with a way to just define custom per-message actions (and message list swipe-actions).
For example, I would like to write a message swipe action that calls out to my plugin, giving it the full message as input, where I could add parts of the message to a Trello list (filtering the subject, body, and attachments appropriately) and then return a response back to Aquamail notifying that the message should now be deleted, or marked read, or moved to another folder, etc.
