v8.0.0

This major release makes react-waypoint have a smaller footprint in consumer bundles. It's pushed as a major release because of a potentially breaking change in how we expose the es module in package.json.

Full list of changes:

• Add es module entry point in package.json
• Type Waypoint class properties as static
• Let proptypes be removable in consumers production bundles

Thanks to @Andarist and @cecchi for all the changes!