Merge default options before resolving animation options
Command animations did not take default options into account when resolving animation options.
This commit fixes that, TopBar options still need to be addressed.
[Breaking[ Modal refactor
* [Breaking] Showing modal removes the previously visible ViewController from hierarchy
* Modal implementation does not rely on Dialog
* Modal view is added to `content` layout
* Overlay is added to `root` layout, on top of the application's content
* Introduce StackControllerBuilder
* Show modal with animation
* Dismiss modal with animation
* Add previous modal at index 0
* Add root at index 0
* dismissAllModals dismisses only top modal with animation
* Rename TopBar.animateHide to animate
also fix some options in playground app
* Consolidate topBar visibility in childWillDisappear
* Rename BottomTabs.animateHide to animate