Issue #996696 by ygerasimov, logaritmisk, fago, indytechcook, wizonesolutions, fearlsgroove, Damien Tournoud, stella: Support revisions in Entity API.

 #1290986 fixed the entity-test module implementation to avoid using entity_load() in hook_entity_info().

 #1027908 patch by fago, drunken monkey: API change - entity_load() should always return entities keyed by ID, not name. See #1027908-50 for details.

 #1008810 overhauled exportable entities so that all entities are stored in the database. Upgrade for modules making use of exportable entities is required, see #1008810-8.

 #988780 API Change: merged both modules into a single one. Read http://drupal.org/node/988780#comment-3834560 for a detailed description of the changes.

 #990558 Entity CRUD: follow core and allow reacting on changes via $entity->original, including tests.

Entity CRUD: help entity types to implement their label() and uri() callback in a way they are alterable, but ease to use.

Entity CRUD: provide entity_view(), entity_build_content(), default implementations and a default template to support modules implementing viewing.

 overhauled the entity CRUD API to be a full module dependency, thus using it without introducing the dependency isn't possible any more. That way we are able to roll out updates much easier and to provide multiple EntityDB base classes, one being extendable via faces and one not.

improve testing module to use the entity API for the entity types too and use the entity_test_type for testing exportables

imported intitial code - basic CRUD functionality is working fine. includes a test case with a test module.