v0.3.0

This is a significant upgrade to how scroll behavior is handled.

Instead of asynchronously updating scroll position on a timer after the location update, this release updates scroll position immediately after the location update. This should avoid flashes of the incorrect scroll position.

The current API has never supported asynchronous React Router transitions particularly well, and now it really doesn't support them in any particularly elegant way. We now explicitly note this given the change to update scroll position synchronously.