Album loading performance

[SoongNoonien]

The album(-cover) loading performance is improvable. This issue is to provide a place for discussion on that topic. It has been extracted from #39.

[SoongNoonien]

The newest commit (4245b40) changes the album loading a bit. Initial GUI blocks in combination with large artists (many albums) should now be gone. I also separated the fetching/locating of the covers from the actual loading of the albums which decreases the initial time needed to display the albums without their covers. Sadly the overall time did not really decrease. The complete procedure is now run in a separate thread using python's threading module but this should manly increase the reliability and not the performance.

@dgcampea It would be really nice if you could test these changes.

[dgcampea]

I can confirm that 4245b40 in general improves the responsiveness of the GUI (previously it would stutter when changing between album artists).

The listing of "all artists" still takes a while but the times seem to have gone down as well.

[dgcampea]

Might be worth a look (haven't looked too deeply into it yet):

• https://github.com/begnac/ampd
  • https://github.com/begnac/gampc