title: mvvmcross ios lock portrait orientation for specific MvxViewController
body: <p>I have solution in Xamarin mvvmcross which support for IOS portrait and landscape screen orientations. IOS 8.0
  I would like to add new MvxViewController but lock it only on Portrait mode.
  I searched in Internet examples for ios swift, xamarin forms but all of this are not applied for mvvmcross solution
  Is there way how I can lock Portrait mode only for one screen with Xamarin mvvmcroos?</p>
  
  <p>Thank you</p>