React Router 2 support

[bdefore]

With release 3.0.0-beta1 we now have support for React Router 2.0 here's their upgrade guide The diff is more or less here: 899ebfd...8983e42

This opens up some new ways to attempt to resolve #16 among other wins.

Still todo / regressions from 2.x (hold back if any of these are important to you):

• fix devtools, it needs to get history differently
• scroll-behavior needs to attach to history differently, is disabled for now
• update or remove getStatusFromRoutes, which can no longer work the same
• add redux-simple-router back to package.json when updated api release is cut

[bdefore]

Removing scroll-behavior as it may not be what people want, and it will require a revisit with RR2 anyway.