Issue #1620010 by dawehner, ParisLiakos, plach, jibran: Move LANGUAGE constants to the Language class.

Issue #1877638 by fago, Gaelan, YesCT, das-peter, tim.plunkett, smiletrl: Rename getOriginalEntity() and remove duplicated functions from ConfigEntityBase.

Issue #1446382 by plach: Need a reliable way to determine if a specific bundle for an entity type is translatable.

Issue #1818556 by das-peter, plach, fago, Berdir, vijaycs85: Change notice: Convert nodes to the new Entity Field API.

Issue #1807800 by plach: Added status and authoring information as generic entity translation metadata.

Issue #1877632 by fago, jhodgdon: Improve comments and clean-up code for EntityNG and the TypedData API.

Issue #1869250 by fago, Berdir, das-peter, YesCT, mradcliffe, fubhy: Various EntityNG and TypedData API improvements.