Model Validation

Squashed commit of the following:

commit 2ba8510f8a3409f698a2a408dd635de9205d5143
Merge: 3ea350c f7305b2
Author: Márcio Almada <marcio3w@gmail.com>
Date:   Wed Oct 30 03:11:08 2013 -0300

    Merge branch 'validation' of https://github.com/beneditocarlos/redmodel into validation

commit f7305b204286fa254caf65d9459a080e0401e4ec
Author: Benedito Carlos Almeida Capela <beneditocarlos.bc@gmail.com>
Date:   Fri Oct 25 16:47:22 2013 -0300

    Update composer.json

    Added respect/validation dependency

commit 634d9bc04d8a4fc7812b57b939f3972e6216a2d4
Author: Benedito Carlos Almeida Capela <beneditocarlos.bc@gmail.com>
Date:   Mon Oct 14 12:53:34 2013 -0300

    integration model validation