1.x branch incompatible with Drupal 8.3

Drupal core 8.3 added two methods to the ContentEntityBase class and interface. TokenAuthUserInterface implements UserInterface which implements ContentEntityBaseInterface. Because the methods are missing from the TokenAuthUser class, it breaks when you update to drupal 8.3.x.

I know the 2.x branch is where new development is taking place. We have a few sites that use this module and we are not yet ready to update to the new architecture for the 2.x branch, but we would like to update drupal core to the 8.3.x version.

I have create a quick patch to fix this. This will allow us to update to 8.3.x while we restructure our site to work with the 2.x branch of the module.