Replace Amarok's context view with a QML rewrite

First integration of the mockup, further development will happen here

DIGEST:
The initial work on Amarok's Context View has just been merged. This means a
much improved UI which will eventually lead to the development of Amarok
3.0, or at least a mobile version. The current result is still non
functional and suboptimal, but already shows promising results. A blog
post describing this work will soon follow.

Signed-off-by: Riccardo Iaconelli