GridView snapping issues

Start tesla and flick the application open in the switcher at launch. Note how it stays
centered horizontally. Open and minimize two more apps, and note how the third app
is shown in the left column, with the first and second app peeking in from the side. This
is not the desired behavior; when there is more than two applications open, the screen
should always contain three or four applications fully visible (i.e. the right-hand column
should never be empty).

Note how changing the preferredHighlightEnd on line 36 of ZoomedOutView.qml to

preferredHighlightEnd: preferredHighlightBegin + cellWidth*(count <= 2 ? 1 : 2)

does not help; note how the left-hand column now can also be made empty, and it is
possible to drag and release the view in ways that the columns are not snapped to one
side or the other at all, even though snapMode is GridView.SnapToRow.