closes #1694

* topBarNoBorder for ios

* Unit tests for topBarNoBorder

fixes #1675

* 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

* Renamed onStop/onStart to didAppear/DidDisappear

* This did't make it!

To match the rest of the styling

As the screen api document mentions that it can be done statically, it's best to mention it here as well.

* Revert "Add custom bar button item class (#1641)"

This reverts commit 80ae102456.

* Revert "Export `Navigator` class for public use (#1647)"

This reverts commit 1770113321.

* Revert "Hide back button when calling resetTo (#1469)"

This reverts commit 518e372e05.

* Revert "Add isRootLaunched implementation on Android"

This reverts commit 6f4aca32a6.

* Revert "Fixed LightBox not updating overlay width/height on rotate (#1461)"

This reverts commit 54d2531720.

This allows for custom React Native views to be rendered as a bar button item in the navigation bar.

* Make Navigator Public

* Make Screen.js export both Screen and Navigator

* Update Navigation.js to import Screen correctly

* Make Navigator public for Android too

* Forgot to export after importing

* ESLint fix

* ESLint fix

* ESLint Fix

* ESLint Fix

* 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

* screen Background Color iOS

* ios v2 topBarTextFontFamily

returns true if NavigationActivity is resumed (startApp was called)