Throw exception when scalar is set on mutlivalue

Related to: update [nt:unstructured] set phpcr:classparents = 'Symfony\Cmf\Bundle\RoutingBundle\Model\Route' where phpcr:classparents = 'Symfony\Cmf\Bundle\RoutingBundle\Model\Route';

In the PHPCR-Shell it is possible to do an update on multi-value properties with a scalar (this actually works, but throws Warnings).

This is a problem in PHPCR-SHell, but also in Jackalope as this should not be allowed.