#1005532 Support different use-cases of options list and added label() helper method to the wrapper classes.

allow making use of the special data type 'entity' in hook_entity_property_info() to describe a generic entity reference.

 #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.

 #708268 some metadata wrapper improvements, in particular fixed property updates to be properly reflected in parent data structures. API change: value() now doesn't throw an exception for not set properties any more, but returns NULL.

 #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.