external display mirror mode is now default

- also cleaned up ofxiPhoneAppDelegate up a little bit,
  - cleaned up formatting.
  - including ofxiPhoneViewController class reference in the
ofxiPhoneAppDelegate implementation file.
  - adjusted iosCustomSizeExample to include a reference to
ofxiPhoneViewController
Merge pull request #2200 from julapy/ios-mirror-mode-by-default

ios external display mirror mode is now default