title: AngularJs submit form and reset $pristine state
body: <p>Taken this form as example <a href="http://plnkr.co/edit/fHEBw6dDdG3IVgnmCLb7?p=preview">http://plnkr.co/edit/fHEBw6dDdG3IVgnmCLb7?p=preview</a><br>
  How can I put the <code>$pristine</code> state of the form to true after the <code>SAVE DRAFT</code> button is pressed?</p>