look for local artwork before Last.fm
display and cache album art from any source in the artist's album listing
Merge pull request #212 from mafrosis/cover-art

Display and cache album art from any source in the artist's album listing
local covers: musicPath can be http://host:port/path again
Merge pull request #214 from DrVanScott/master

fix for regression of #132: musicPath can be http://host:port/path again