Save changes to CD data locally

[gwalla]

Online CD databases only go so far. In certain circumstances, it would be useful if Exaile could maintain its own small local database of CDs. Currently, if you try to edit track information on a CD, you can make a temporary change that lasts as long as the Audio CD playlist is open, but disappears when it is closed—if you open the CD again, you have to manually make the changes all over again. This makes it a pain to play CDs that aren't in the online databases (e.g. a rare album, or a CD-R made by a friend). It also makes it hard to fix incorrect information from the online databases.

The local DB would only store information when the user sets track info on a CD track. It would be checked before checking the online database. If it contained incomplete information, or no information, on the current CD, the remainder would be filled in from the online database. The distinction would be invisible to the user.