The following PR introduces improved support for Context api and other api's which wrap the root view.

## Context api
Navigation.registerComponent('navigation.playground.ContextScreen', () => (props) => (
  <TitleContext.Provider value={'Title from Provider'}>
    <ContextScreen {...props} />
  </TitleContext.Provider>
), () => ContextScreen);

## Redux
Navigation.registerComponent('navigation.playground.ReduxScreen', () => (props) => (
  <Provider store={reduxStore}>
    <ReduxScreen {...props} />
  </Provider>
), () => ReduxScreen);

## Plain Component - not changed
Navigation.registerComponent('navigation.playground.MyScreen', () => MyScreen);

This PR also upgrades the TypeScript version to 3.2.0 and RN version used in the playground app to 0.57.7

* New Android build flavor - `reactNative57_7`
* Unit test coverage is disabled, for some reason it broke after upgrading to RN 0.57.7

* Support RN 0.55.4

This commit adds support for RN 0.55.4 by introducing version specific build flavors - reactNative51

* Update scripts after introducing build flavors

* Update Android installation instruction on specifying build flavor

* update api jsdoc

* iniline some properties

* add typedoc

* remove typedoc

* try again with typedoc

* explicit types

* docs

* try handlerbars

* working on docs

* update docs

* html

* removed old md

* trying stuff

* fix lint

* working on docs

* trying with themes

* something works

* trying to use automatically

* working on docs

* docs

* docs

* docw

* auto docs

* rename

* local-docs no cache

* automating

* ts-node

* working on something cool

* temp

* try fix travis

* Revert "try fix travis"

This reverts commit 5bcb54659b.

* removed dead files

* main readme inside docs

* softlink

* softlink

* docs working