* 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

This reverts commit f7ec9ee840.

* Add support for setting larget title text attributes

* Add documentation for setting large text attributes

See https://developer.apple.com/documentation/uikit/uinavigationbar/2919946-largetitletextattributes

This reverts commit 883dcfe49f.

* fixes #2524

* added the ability to change the backing controller's preferredContentSize through props.

* added some documentation outlining preferredContentSize and modalPresentationStyle properties

This reverts commit abdb6e90a0.

* setTabButton -> has now the property 'label' to change the label of the TabButton

* Add to documentation

* [BugFix] use i instead of 0 to check all TabItems

* setStyle -> to change bottomTabBar

* update android

* remove hass...-functions

* update iOS set TabStyle

* iOS change icon color on buttonTabColor has been changed

* iOS update style-update rutine to update each viewcontroller in a NavigationViewController
tabButtonColor improvement

* iOS add forgotten header declaration

* iOS fix c&p error

* [Android] initialize colors for an empty AppStyles-Object

* [Android] fix update style of tabbar on display screen

* [Android] revert eventbus changes
[Android] apply guyca's solution

* [Android] rn 50 compatibility

* remove comment

* Revert "Improve getCurrentlyVisibleScreenId on iOS with drawers. (#2052)"

This reverts commit 2c30a52bb9.

* Revert "introducing navbar shadow on iOS (#2339)"

This reverts commit 8fd496e0c9.

* Revert "This fixes an issue with a custom title-view (which has a title and a subtitle) appearing at the left side of the nav-bar instead of the center during a transition animation: when a screen with this title-view is being pushed or when you pop back to it. (#2384)"

This reverts commit 3f7f6c2612.

* Revert "Now allowing the custom nav bar to take up the whole space on iOS (#2306)"

This reverts commit 74a02ccfc5.

* adds shadow opacity, shadow color, shadow offset, shadow radius to navbar for ios

* mentions ios shadow in styling-the-navigator docs

This happens because the title-view is being created again when RVVViewController appears. There's probably no point in setting the title-view again with the same data when it already has it. The title view setup is done anyway in RCCNavigationController.

This can be easily reproduced by calling "this.props.navigator.setSubTitle({subtitle: 'a subtitle'});" from the constructor of a pushed screen.

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

- Also the custom nav bar reacts well to orientation changes
- Fixes: https://github.com/wix/react-native-navigation/issues/1893

* It now works well on iOS 11 as well

* v1.1.314 [ci skip]

* Added optional fixedWidth property to the Android side menu

    - Fixes: https://github.com/wix/react-native-navigation/issues/510

This reverts commit 076ee7311e.

setTabButton -> has now the property 'label' to change the label of the TabButton

iOS update style-update rutine to update each viewcontroller in a NavigationViewController
tabButtonColor improvement

Add the preview and pop feature

To use the feature you simply call `navigator.push()` but with additional parameter `previewViewID` which is a React Node.

```js
<TouchableOpacity
  onPressIn={() => this.props.navigator.push({
    screen: 'screenid',
    previewView: this.viewRef,
    previewActions: [{
      title: 'Foo',
      style: 'selected', // none, selected, destructive
      actions: [{ title: 'Bar' }],
    }],
 })
/>
```

This fixes a bug where navigator-level styles could override styles on a specific button.

This reverts commit 9f2f15bc4f.

* Support iOS 11 prefersLargeTitles #1643

* better and more simple version checking and setting

This only happens when you are using react-native@0.48.3, and your XCode is in version 9.0

See https://github.com/wix/react-native-navigation/issues/1446#issuecomment-319858633

https://github.com/wix/react-native-navigation/issues/1446

* added method for getting the currently visible screen ID. Can be useful to decide if logic should be applied according to screen visibility, for example: set buttons/title dynamically, or even determine that you don’t need to show the same screen again if it’s the current one that’s showing

* Implement getCurrentlyVisibleScreenId on Android

Can be used statically:
Navigation.getCurrentlyVisibleScreenId() - returns the unique screen
instance id

With a navigator instance:
await this.props.navigator.screenIsCurrentlyVisible() - resolves a
promise that checks if the current screen is visible

* Add screen visibility listener which can be registered globally

API
new ScreenVisibilityListener({
    willAppear: ({screen, timestamp}) => console.log(`Displaying screen ${screen}`),
    didAppear: ({screen, timestamp}) => console.log(`Screen ${screen} displayed in ${Date.now() - timestamp} millis`)
  }).register();

todo
* Add timestamp to modal, resetTo
* implement unregister
* implement iOS

* Add global screen visibility listener to example app

* Think I better assign a value to emitter

* Send timestamp in resetTo

* Moved listener to library, it can be deleted from the app

* Add push and resetTo buttons to pushed screens

* Send appear/disappear events after animation ends

* Pass pop timestamp from js

* Send timestamp in popToRoot

* Add popToRoot button in push screen

* Add few navigation buttons to modal screen

* Pass timestamp to tabs

relevant only to first/initial tab

* Update timestamp when navigating between BottomTabs

* Send screen visible events after modal dismiss

* log willDisappear and didDisappear

* Report both start and end timestamps

* Implement unregister

* Send NavigationType parameter in visibilityEvent

This indicates the type of the navigation command that triggered the visibility change

* Rename pushInitialScreen to more explicit name

* Fix duplicate initialScreen visibility events

* Update screen visibility log statement

* Show popToRoot in modal screen only if screens were pushed

* implement global screen event for iOS

* fix lint issues

[iOS] Added ability to set static(root) background image

added 03d380f8a9 back and also applied this fix https://github.com/wix/react-native-navigation/issues/428#issuecomment-278268928 on top of it

* Fix disabledBackGesture.

This `return self._disableBackGesture ? self._disableBackGesture : YES;` check is incorrect, it's the same as `true ? true : true;`.
Also `_disableBackGesture` was never set. We should just `return disabledBackGestureBool` (bool value of the prop).

* [iOS] Enable back swipe gesture when a navBar is hidden. Resolves this issue: https://github.com/wix/react-native-navigation/issues/930

added 03d380f8a9 back and also applied this fix https://github.com/wix/react-native-navigation/issues/428#issuecomment-278268928 on top of it

* Revert accidental commit: 3cdb1b37f6

Add setSubTitle implementation for iOS + docs

Custom title view in navigation bar support in `navBarComponentAlignment:'fill' | 'center`

* Add ability to set attributes of navigation bar buttons separately.

* Added ability to set button style when calling `setButtons` method.

* Add documentation.