This is working on the screen API too, however it's not included in screen API, only on top-level screen

There's a roundabout manner of obtaining the react context on initialisation that is null on some instances (https://github.com/wix/react-native-navigation/issues/2695), including errors on startup that prevents debugging on console. (For instance, throwing an error on index before starting the app)

It is solved by sending the same context given on method onReactContextInitialized, instead of discarding it and calling getReactContext.

* for iOS

* first try for android

* iOS indent

* Android Indent

* Update platformSpecific.android.js

* Update NavigationReactModule.java

* Update NavigationCommandsHandler.java

* Update platformSpecificDeprecated.android.js

* Update platformSpecificDeprecated.ios.js

closes #2966

Test jenkins

Avoids a null pointer exception when not passing { side: "left" } to navigator.toggleDrawer() on Android

check jenkins

* fix navigatorStyle don't work on Drawer

* Fix lightbox dismiss on Android

* Update LightBox.java

* Add splash screen tut in third party lib support list

* Revert the old drawer commit

Added a missing curly bracket in top tabs example.

fixes https://github.com/wix/react-native-navigation/issues/1771

* add back button to screens pushed to stack
* resolve tab icon from root screen, instead of first pushed screen
* omit components object from tabs

* Add support for react-native 0.52.0

* Refactore a bit

1. Rename `DevCommandsHandlerProxy` to `DevHelperProxy` so it reflects the changes in RN. See d19afc73f5 .
2. Add few comments to show which code is used on `RN >= 0.52` and which on `RN <= 0.51`.

* Now allowing the custom nav bar to take up the whole space on iOS

The custom nav bar on iOS was really just a custom view applied to the title of the navigation bar.
There were problems with this approach, because the navigation bar messes up the frame of the title very frequently, especially when the orientation is changing. That behaviour is accepted when the title is a label, but not when we have a custom component.

With this pull request the custom nav bar component can take up the full width of the navigation bar, no matter what orientation we're at.

* Added mix of native btns and custom component on the Custom TopBar screen of the example project

The initial modal screen got animated twice, this regression was introduced in #2761.