Comment 3 for bug 720351

Perhaps this should be in a separate RFE, but there's a feature that would be great: optional three-way merge when the file on disk is detected to be newer than the last open/save time for the file in the editor.

It would work like this:
 - Scribes takes a snapshot of the file when opened or saved. This is stored in Scribes memory and is only for internal use.
 - If a newer file is detected on disk than the timestamp for the snapshot (and content differs from the snapshot), Scribes offers to either (1) reload from the one on disk, dropping any changes in the editor, (2) ignore the updates on disk, or (3) perform a three-way merge with the snapshot as the BASE, the file on disk as OTHER, and the content of the editor as THIS.

There are good Python libraries for performing this sort of merge, and it would be easy to make the feature only available if they're installed.