Robustness
Avoid NPE when notifying user whereas getResources() returns null
Avoid NPE in playlist fragment by storing the activity in an attribute on activity creation (the getActivity() method returns sometimes null after a rotate or on wakeup)
Revert fix to not re-download album cover
Refrains the view to be refreshed sometimes whereas it should be
Robustness
Avoid NPE when notifying user whereas getResources() returns null
Avoid NPE in playlist fragment by storing the activity in an attribute on activity creation (the getActivity() method returns sometimes null after a rotate or on wakeup)
Robustness
Avoid : ERROR/AndroidRuntime(26128): FATAL EXCEPTION: MPDStatusMonitor
                java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
                at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
                at java.util.ArrayList.set(ArrayList.java:481)
                at org.a0z.mpd.MPDPlaylist.refresh(MPDPlaylist.java:229)
                at org.a0z.mpd.MPDPlaylist.playlistChanged(MPDPlaylist.java:172)
                at org.a0z.mpd.MPDStatusMonitor.run(MPDStatusMonitor.java:122)
Robustness => Avoid : java.lang.IllegalStateException: Content view not yet created
                at android.support.v4.app.ListFragment.ensureList(ListFragment.java:328)
                at android.support.v4.app.ListFragment.setSelection(ListFragment.java:198)
                at com.namelessdev.mpdroid.fragments.PlaylistFragment$3.run(PlaylistFragment.java:320)