Adds chooser if pbs site lists multiple videos.
Adds chooser if pbs site lists multiple videos.

pcwalden/get-flash-videos,vladrich/get-flash-videos,vladrich/get-flash-videos,njtaylor/get-flash-videos,karjonas/get-flash-videos,pcwalden/get-flash-videos,pcwalden/get-flash-videos,njtaylor/get-flash-videos,njtaylor/get-flash-videos,monsieurvideo/get-flash-videos,karjonas/get-flash-videos,monsieurvideo/get-flash-videos,monsieurvideo/get-flash-videos,vladrich/get-flash-videos,karjonas/get-flash-videos