* Revert "merging buttons fix"

This reverts commit 74077bbc55.

* Revert "fix undefined buttons"

This reverts commit e3b4d15a06.

* Revert "fix e2e"

This reverts commit 05b3f5808f.

* Revert "Handle merge buttons style"

This reverts commit 9c705402eb.

* Add background component with MATCH_PARENT height

* temporary solution for merging button color

This commit introduces two temporary options to control button colors
* rightButtonColor
* leftButtonColor

These options can be used to color buttons. Colors defined in buttons take
precedence over these two options.

* Get buttonColor options from resolved options

* leftButtonColor & rightButtonColor support - iOS

* Disabled color

* disabled buttons color support

* Rebase fixes

* empty commit

This reverts commit 4c519acae8.

* Refactor peek and pop

* Rollback some XCode stuff

* Added tests for touchablePreview event

* Also fixing searchbarcancelpressed event

[BREAKING] Call Navigation.events().bindComponent(this) to listen to lifecycle events

This commit introduces breaking changes to the way components listen to RNN events.


Background

Up until now, components could handle navigation events by implemented a set of callbacks:
* componentDidAppear
* componentDidDisappear
* onNavigationButtonPressed
* onSearchBarUpdated
* onSearchBarCancelPressed

While this worked fine for the most part, this was completely broken for HOCs as RNN invoked these methods only on the registered component (top most HOC), leaving it to the user to propagate these events down the HOC chain. See the discussion in #1642 for more details.


Solution

In order to support HOC use case, we're introducing a new api which will let any Component bind itself to receive navigation events:

```js
class LifecycleScreen extends Component {
  constructor(props) {
    super(props);
    this.subscription = Navigation.events().bindComponent(this);
  }

  componentWillUnmount() {
    // The subscription is removed automatically when components unmount, but they can be explicitly removed as well by calling `this.subscription.remove(); `
  }
}
```

It's still the users responsibility to propagate the `componentId` down the HOC chain, but by binding a component to RNN, it will be able to handle events as expected. Multiple components can be bound for the same `componentId`.


Consolidate event names

* onNavigationButtonPressed -> navigationButtonPressed
* onSearchBarUpdated -> searchBarUpdated
* onSearchBarCancelPressed -> searchBarCancelPressed

[BREAKING] Buttons refactor

* Support setting single button
```js
  topBar: {
    rightButtons: {
    }
  }
```
* [BREAKING] Rename button.title to button.text

* Set TopBar default background color (white)

This commit introduces an option to control the way components are pushed into the stack.
When pushing components into a stack, they are pushed the moment they are measured.
If `waitForRender` is true, components will be pushed only after the initial render.

api:

```js
options: {
  animations: {
    push: {
      waitForRender: true
    },
    showModal: {
      waitForRender: true
    }
  }
}
```

Unmount react views when bundle load completes

Users providing their own ReactNativeHost implementations should implement BundleDownloadListenerProvider
and make sure they set DevBundleDownloadListener when ReactInstanceManager.

* V2: Peek and pop

* Add event when preview is dismissed in non commit mode

* tslint

* Refactor playground. Document preview api

* Added width prop

* Implement hybrid push/preview button

* Fixing small linting errors

* Refactor TopBar options, introduce title options

* Update background to new api

* Refactored topBar options on iOS

* Initial react component in TitleBar android

* set height to react view in TitleBar

* fix tests and lint

* ios unit tests fix

* Change topBar backgroundColor to Color object

* StackLayout implementation

Unfortunately, this commit also contains a lot of refactoring and a few
bug fixes relating to styles.

* TopBar is not part of Component, instead it's a part of StackLayout
  and shared between all components pushed to the stack Similar to iOS.
* Handle ScrollEvent in ReactView instead of passing the listener down
* Implement Fraction and Text null objects for style params
* Converted a few style params to null objects. This fixes some styles
  being applied even when they were not specified explicitly.
* Stop sending null promise to commands
* Seperate push and pop into animatePush/push and animatePop/pop
  to avoid boolean param

* Adapt TopTabs to new API

* default options support
* refactored navigation options

* refactored e2e tests to work with testIDs

* lint fix

* android e2e fixed

* push/pop promise

* tests

* modal

* other

* fix tests

* probably test fix

* changed this.props.id to this.props.containerId

* fixed js tests

* refactor