use fast (GPU) scaling in album grid to improve scroll smoothness

ui/widgets/albumcard.go

@@ -34,7 +34,7 @@ type albumCover struct {
 func newAlbumCover() *albumCover {
 	a := &albumCover{}
 	a.ExtendBaseWidget(a)
-	a.Im = &canvas.Image{FillMode: canvas.ImageFillContain}
+	a.Im = &canvas.Image{FillMode: canvas.ImageFillContain, ScaleMode: canvas.ImageScaleFastest}
 	a.Im.SetMinSize(fyne.NewSize(200, 200))
 	a.playbtn = &canvas.Image{FillMode: canvas.ImageFillContain, Resource: res.ResPlaybuttonPng}
 	a.playbtn.SetMinSize(fyne.NewSize(60, 60))

ui/widgets/albumgrid.go

@@ -98,6 +98,7 @@ func (ag *AlbumGrid) Reset(iter backend.AlbumIterator) {
 	ag.albums = nil
 	ag.fetching = false
 	ag.done = false
+	ag.highestShown = 0
 	ag.iter = backend.NewBatchingIterator(iter)
 	ag.fetchMoreAlbums(36)
 }