title: how to lock portrait orientation for only view in ios 7
body: <p>I have created an application for Iphone and Ipad that is composed from two main views with navigation controller. The navigation controllers are inserted into tabBar controller.
  I would like lock the main views to Portrait orientation and only a subview of a navigation controller trigger the possibility orintation to Partrait and Landscape.
  Is it possible?
  How Can I do?</p>
  
  <p>Thanks    </p>