Motion 3 - Swift 4.2 Support

• Updated to swift 4.2.
• pr-45: Fixed issue-44, view is hidden below status bar during call.
  • issue-44: View is hidden below status bar when a call is active.
• pr-50: Allow framework to be linked from extensions.
• pr-53: Bug fixes and MotionViewTransition.
  • Made MotionTransition.{start|update|finish|cancel} methods public.
  • Changed to updating model before firing animations for CALayer animations.
  • Added reverting XXForNextTransition options back to default.
  • Fixed issue when interactive transition was cancelled it was calling finish instead of cancel.
  • Fixed appearance transition callbacks for transition cancellation.
  • Fixed resume time was calculated incorrectly.
  • Fixed ~0.001 seconds precision issue by storing current time.
  • Added MotionViewTransition to make transitions of views possible.
• pr-54: Added setCompletionCallbackForNextTransition.
• pr-55: Fixed UITabBarController had userinteraction enabled during transition.