osx: added dumb plugin
osx: fixed dumb dylib name
Merge pull request #33 from cboxdoerfer/master

gtkui: add custom colors for playlist columns
cocoa: added status bar
Merge pull request #34 from cboxdoerfer/master

gtkui: alternate row color only within a group
gtkui: draw only one group title when group is pinned and some other minor performance optimization