Made the exported types editable and also the admin screen friendlier with displaying label instead of machine type.

Issue #1233448 by clemens.tolboom: Fixed Error on admin/structure/relation/generate when no relation types defined yet.

Issue #1270550 by naught101: Advanced fieldset for arity, transitivity, etc. in relation types form.

Issue #1270522 by webchick: fixed Relationships type table does not conform to core UI standards when no rows exist.

Partial rollback of commit by naught101: change name back to label, except on relation_type editing form.

Issue #1165286 by naught101: Changed Label->Name everywhere, fixes machine_name. Also fix some coding inconsistencies.

Issue #1163876 by naught101: Fixed Relation Add form does not pick up bundles described in hook_entity_info_alter().

relation->entity_keys is now relation->endpoints[LANGUAGE_NONE]. Free MongoDB support. Less custom code. Bliss.

made the delete form working, removed the database query from there and there is a test for relation_query() now consequently.

AJAX-ification of dropzone block. Fixed machine name on admin page. Move of relation type load logic into a helper.