Make responder chain tampering compatible with 10.10
Make responder chain tampering compatible with 10.10

There is a subtle change in that our view controller is inserted as next responder for the view rather than the window.

This is consistent with what is done by default on 10.10, for details see https://developer.apple.com/library/mac/releasenotes/AppKit/RN-AppKit/#10_10ViewController

Closes shpakovski/MASPreferences#37

konstantinpavlikhin/MASPreferences