fixed the scrollbar position in albumwidget.
fixed the width of the artists column in artists view.
player: Skip unplayable tracks in Songs view and error icon is now visible.

removed theerror in discoverer in the previous commit.

the discoverer should check for the next url.
Merge pull request #76 from sumansai14/master

- Fixed the scrollbar position in album widget
- Don't remove the error icon in unplayable tracks in Songs view