Fix iOS8 orientation handling

**Update: I am now maintaining this project from https://github.com/sammcewan/WYPopoverController which is referenced in the latest version of WYPopoverController on Cocopods**

Fixes to orientation for iOS 8. Have taken the approach of not touching anything for < iOS 7.

I use WYPopoverController on another project in more complex ways so will be sure to remediate any of these issues too.