Manual mapping of track names

[ghost]

This issue was automatically migrated from Google Code.
Original author: [email protected] (April 21, 2012 20:08:32)
Original issue: google-code-export/beets#377

[dokterbob]

I guess this patch needs a more in-depth description. I would suggest the following:

Apart from the existing choices (Apply, skip, etc.) an extra choice should be added: 'Apply and edit'
Choosing this option will allow the user to edit tags for each track and for the complete album before writing them to files.

This should also cover the 'manual' option suggested in #129 and could possibly be handled as a single issue with it.