New features

Pick up suggestion from #2808313 @lisastreeter

Added new class EntityEventSubscriber which implements all methods in the same class.

Rewrite of processing

This is a alpha release for the next feature release of Drupal 8. Alphas are good testing targets for developers and site builders who are comfortable reporting (and where possible, fixing) their own bugs. Alpha releases are not recommended for non-technical users, nor for production websites. More information on alpha releases.