Introducing a new icons theme for the coverart browser

Hi, I have been working on a new them for a while.  The goal of this theme is to be easier on the eyes and less distracting for the user.  Enhancements on this theme are:

- Pixel snapping.  Whenever possible, I have tried to align the icons to the pixels on the screen to get less blurry icons.
- Smaller up and down arrows.  This would be nice if we could put them closer to the sort icon.
- Complete redesign of the playlist sprite.  Removal of the tile icon for library view since now it can also be in coverflow mode.
- Genre icons tweaked individually to keep the same tone between the bold shapes and finer ones.
- Greyed out effect when the genre is unknown.  
- Redesign of the decade sprite. It now only shows the decade number without the calendar for better clarity.