Correct the image fade in.

When going from the loading image to the loaded image, transition
between the two, not via a transparent drawable over the top.  This
fixes an issue where the "loading" image appears under any transparent
parts of the loaded image.
Update to v9 of the support library.
Explicitly keep the model class constructors.

Without this they get stripped by ProGuard, leading to exceptions in
SqueezerBaseListHandler.
Make sure that scrobbling code does not depend on notification preferences.

Move the scrobbling code ahead of the check to see if the user enabled
the ongoing notification feature.

Track the state of the scrobbling preference, so that if the user turns
it off after scrobbling started the correct "stop scrobbling" intent
is still posted after the song finishes.
Make scrobbling simpler to control.

Instead of asking the user which scrobbling client they'd like to use,
query to see which scrobbling intent broadcast receivers are available,
and use that, favouring ScrobbleDroid over SLS if both are available.

Make the scrobbling preference a simple checkbox, and upgrade from the
user's previous preference if it exists.

Tell the user if they enable scrobbling but no suitable app is installed,
and present them with a list of possible apps to use, linking to Google
Play for ease of installation.
Rename some variables after overzealous Eclipse refactoring.
Dutch translations for new strings, contributed by Sebastian van Winkel.
Update AndroidManifest.xml and NEWS ready for the 0.9 release.
Danish localization
Fix ClassCastException in download from current playlist

SqueezerCurrentPlaylist can't be cast to SqueezerAbstractSongList,
because it no longer extends SqueezerAbstractPlaylist (as the callback
requires special handling of the currently playing song).
The downloadSong method is moved to SqueezerBaseActivity thus
eliminating the need to cast. (and the need to duplicate it in the
music folder list).
Update mapping file for 0.9 release.
Note the source of an NPE for future work.
Merge commit 'cca16327e06be57c1e2cab3734322a6df2c5ad48' into actionbar

* commit 'cca16327e06be57c1e2cab3734322a6df2c5ad48':
  Note the source of an NPE for future work.
  Update mapping file for 0.9 release.
  Fix ClassCastException in download from current playlist
  Danish localization
  Update AndroidManifest.xml and NEWS ready for the 0.9 release.
  Dutch translations for new strings, contributed by Sebastian van Winkel.
  Rename some variables after overzealous Eclipse refactoring.
  Make scrobbling simpler to control.
  Make sure that scrobbling code does not depend on notification preferences.
  Explicitly keep the model class constructors.
  Update to v9 of the support library.
  Correct the image fade in.