This option property lets us set a top margin to a component which can be useful sometimes
when using statusBar.drawBehind.

screenBackgroundColor was also renamed to backgroundColor

```js
layout: {
  orientation: 'landscape',
  backgroundColor: 'red'
}
```

* Work in progress

* Arbitary changes

* Improvements on API

* Cleanup RNNSplitViewController, allow mergeOptions

* Added documentation and better playground example

* Adding tests for coverage

* Find out why this test is failing.

* Only show split view on iOS

* Add test back in

Hopefully, this will prevent Detox from timing out when a system alert pops up on the screen.

This commit add support for changing the TopBar height as well as changing
the height of custom component used as background

1. Sideenus weren't clickable on Android. It seems the order in which
child views were being added to parent controllers, left or right
before center, were affecting the ability to interact with the menus.
I've changed the code to always add them in a specific order: center,
then left, then right.

I believe this closes issue #2835.

  https://github.com/wix/react-native-navigation/issues/2835.

2. On Android, merging options to open a menu works.

  Navigation.mergeOptions(currentComponentId, {
      sideMenu: {
          left: {
              visible: true
          }
      }
  })

But merging options to close it wasn't working.

  Navigation.mergeOptions(currentComponentId, {
      sideMenu: {
          left: {
              visible: false
          }
      }
  })

3. The bottom tabs controller was reserving a margin space for the tabs
when switching from one to another, regardless of its visibility
settings.

As you can see here: https://github.com/wix/react-native-navigation/blob/v2/lib/src/events/EventsRegistry.ts#L28 nativeEventListener expects an object which is includes name and params but on the iOS side, the native bridge is triggers the event listener but passes wrong object. iOS is passes commandName instead of name. This commit is fixes the problem.

* setRoot({root:{}})

* support setRoot with root, modals, overlays

* Update setRoot calls in playground app to new api

* Update setRoot on Android to new api

currently only supporting root node

* Update setRoot on iOS to new api

* fix unit tests

* New statusBar options format
* Static events

* refactored status bar options iOS

* [Breaking] Pull StatusBar styles to separate object

Currently exporting `backButton` id, usage: `Navigation.constants.backButton`

Pass child ViewControllers in constructor and create tabs in constructor as well

Fixes #2996

* Update docs

Outdated onAppLaunched part is changed

I just started to a project with v2 and I realized this part of the documentation was wrong. I searched a bit and find this 2 commits: 

104e3f97fd

1d2680c5aa

So, that part is probably forgotten

* Modal unmount e2e test

* Modal unmount e2e test changes.

Fixes #3138.

AHBottomNavigation recreates all tabs when some style properties are set.
This commit works around this issue by setting the problematic style properties
only if they are different then current values.

Related to #3132

* Implementation of passing multiple arguments to ImageLoader in order to avoid asynchronous issues and for performance as BottomBar re-creates all views every time an item is added

* removed redundant checks for testId

* Implementation of passing multiple arguments to ImageLoader in order to avoid asynchronous issues and for performance as BottomBar re-creates all views every time an item is added

* removed redundant checks for testId

This prevents the call to mergeOptions from applying statusBar color even
though it was not declared explicitly by the user.

* Set default statusBarBackgroundColor to Black
* Component and Parent controllers now extend ChildController
* Implement return to front logic for ChildControllers
* Apply statusBar color when view appears and returns to front