Stable Bidirectional Infinite Scroll

We struggled to find an existing package that gave us a stable bidirectional infinite scroll out of the box. Users of dispatch.do are often dropped in the middle of a feed and we needed to load historical as well as more recent data without shifting the view.

Open-sourcing a component we wrote to solve this problem. Works with heterogenous rows and pairs well with virtualization libraries like react-window. Pull requests, issue submissions very welcome :)