* Add requirement to DMTraitEnvironment and remove UITabBarItem's conformance
* Setup tests with class objects instead of class names
* mark UIViewController's comformance as open
* Use system dynamic color on iOS 13+
* Swizzling for DMTraitCollection
* Remove override of dm_updateDynamicColors and dm_updateDynamicImages
* Update naming and return UITraitCollection.current directly
* Allow using view controller to observe change