Fix #327 : List cover art progress bar spins forever
- Cover progress bar display is now triggered by the message "onCoverDownloadStarted" sent by the cover manager.
- The cover is then displayed by the album cover listener when it receives the onCoverDownloadStarted message.
- The cover manager sends the onCoverDownloadStarted message when the cover is downloaded from the web (no progress bar when the cover comes from the cache)
remove Log message
Merge branch 'master' of https://github.com/abarisain/dmix into upstr

Conflicts:
	MPDroid/src/com/namelessdev/mpdroid/fragments/AlbumsFragment.java