Entity translation support

I need to know entity type to get the right language using field_language($entity_type, $entity, $field_name = NULL, $langcode = NULL)

I don't like passing around $entity_type, but core does that too :-/ and there is no way I can figure out $entity_type on the spot.

I've added $entity->vfo_entity_type on hook_entity_load so we can use it in field_language()