This PR adds support for setting stack root with multiple children, which is to be expected as stack can be initialised with multiple children.
Closes #4441

* passProps to buttons

* push and pop custom transitions

* refactored defaultOptions

* custom animations support for show and dismiss modal

* refactored transition animations

* unit test fix

* async await for push and showModal

* async await for push and showModal

* refactored custom transitions

* refactored custom animations

* screen Background Color iOS

* ios v2 topBarTextFontFamily

* added topBarHidden to iOS

* minor fix and topBarHideOnScroll

* minor fix

* topBarButtonColor iOS

* topBarTranslucent iOS

* topBarTranslucent IOS minor fixes

* eslint fixes

* minor fixes

* changed setTabBadge to tabBadge and added a unit test in iOS

* added fontSize on iOS

* minor fix

* topBarTransparent

* minor fix

* first dirty custom transition iOS poc. in need of complete refactor and testing

* dirty poc for view transition

* dirty poc of interactive transition

* deleted unNeeded Files

* cleaning

* cleaning, support for interactiveImagePop and backButton custom transition

* cleaning

* merge v2 into custom-transition-animation fix

* merge fix

* merge fix

* cleaning and merge fix

* support for multiple animation in parralel, animations with are not shared element including: velocity, spring, alpha and translate

* last commit should also include these

* added resize mode animation and fixed flickering bug

* refactoring

* first cleaning and another test

* cleaning

* commandsHandler now accepts bridge in constructor, fixed tests, added e2e test

* eslint

* android pop now recieves two parameters - preparation for custom transition

* Refactor + add afterLoad to modal

* merge v2 second try

* merge fix

* merge fix

* fix ios unit tests

* fixed topBarTransparent e2e

* fix js tests

* refactored RNNAnimator, RNNAnimatedView, small fixes

* refactor topBarLargeTitle

* fixed lifycycle bug with componentWillUnmount, small fixes

* fix transparent conflict

* removered Element.js from coverage report

* comment redundent test
(still needs to be discussed), small fix

* removed commented test, moved element.js to adapters