Add (failing) tests asserting StackedBar doesn't draw off-bar labels.
Add (failing) tests asserting StackedBar doesn't draw off-bar labels.

iobeam/plottable,palantir/plottable,iobeam/plottable,palantir/plottable,palantir/plottable,NextTuesday/plottable,iobeam/plottable,softwords/plottable,softwords/plottable,palantir/plottable,NextTuesday/plottable,softwords/plottable,NextTuesday/plottable