* 🎉 WindowScroller supports scrollToIndex prop. (@leoasis - https://github.com/bvaughn/react-virtualized/pull/643)
* 🎉 Allow ArrowKeyStepper to be used as a controlled component. (@mking-clari - https://github.com/bvaughn/react-virtualized/pull/688)
* 🎉New handleScroll method on Grid to better support custom scrollbars. (@5angel - https://github.com/bvaughn/react-virtualized/pull/693)
* 🐛 Added edge-case gaurd to WindowScroller  to prevent calling setState when unmounted. (@liorbrauer - https://github.com/bvaughn/react-virtualized/pull/689)
* 🐛 Fixed edge-case in Grid where setting an initial scroll-to offset with a height or width of 0 caused the scroll-to prop to be ignored when size later changed. (https://github.com/bvaughn/react-virtualized/pull/691)
