Use full classed Profile2 entites on entity_save()

Problem: if you pass a stdClass Object to entity_save() some follow-up modules like Rules assume that they get a full object and invoke methods on it. This leads of course to a fatal error.

Call to undefined method stdClass::type() in modules/entity/includes/entity.property.inc

Here is a patch that uses either a newly created entity class or an existing loaded entity for saving. And I did a little code cleanup, removed totally useless lines.