Prefer artist over album artist.

E.g. when playing a compilation title, one very likely wants to see the real
artist instead of 'Various artists'.

Change-Id: Ie200f2f8b0b90d3470c2e2e4ca6f91f9b117fb1f
halo: some notification misses

PS2: cleanup

Change-Id: I0e8976e51c16e9bca189f447fa62a3d2f062f427
Signed-off-by: Dan Trifan <jimsth@gmail.com>