Basics for identity

- IdentityInterface, which extends ACL and RBAC RoleInterfaces
- GuestIdentity, which extends RBAC AbstractRole and sets up a "guest" identity
Added authenticated identity
Removed identity stubs
Created default listeners
Merge remote-tracking branch 'origin/feature/identity' into feature/mvc-events

* origin/feature/identity:
  Added authenticated identity
  Basics for identity
Refactor towards exceptions
Added Matthews Identity
Added Default Listeners