Fix stacked bar animation.
Fix _getAnimator special case.
Merge branch 'develop' into stack_animate

Conflicts:
	plottable.d.ts
	plottable.js
	src/components/plots/stackedBarPlot.ts
Fix baseline animation.
Remove redundant animator.
Merge pull request #1224 from palantir/stack_animate

Fix baseline animation in stacked bar.