* React Native v0.40.0 fixes

* Implement disableIconTint property on Android TitleBarButtons

* Show contextual menu only on Modal, if showing

* Fix crash if font not set in title bar button parameters

This is mostly a workaround to overcome faults in the simple event bus implementation,
also fixes crash when reloading while modal is displayed.

Animate linear translation also when animating shared element bounds

Separated iOS and Android only properties.

Apply easing on shared element bounds transformation

Animate image scale and bounds

This commit properly animates images with different aspect ratios.
By default, regular scale animator is used which scales up or down the entire ImageView.
If `animateClipBounds={true}` is specified on the **to** `SharedElementTransition`, instead of scaling the View, the actual Drawable bounds and scale is animated which prevents the image from appearing distorted during the transition.

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

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

* Add documentation.

fixes #942

* Send willAppear didAppear for initial screen

* empty commit

- compileSdkVersion 25
- buildToolsVersion "25.0.1"

Support status bar color in Modals

fixes #1034

* Support custom font in the Menu items.

* Fix check for custom font.

Add tabBarTranslucent style option in tabsStyle

This commit adds support for the following style properties:
titleBarTitleFontFamily - string, font name in assets
titleBarTitleTextCentered - boolean, default is false

* adding support for android centered title and custom font

* PR feedback

Support customize icon for left nav button in android

FadeIn ContentView and TopBar when pushing shared element screen

If the screen is pushed with `animated: false` then only TopBar is
animated in. This is a compromise until we expose means to control the
transition of each element on the screen.

Reading the docs I couldn't see a way to simply change the color of the status bar on Android. Only via https://github.com/wix/react-native-navigation/issues/571#issuecomment-267255350 I saw there was a prop to do this.

(Assuming this is Android only since iOS only allows for light or dark).

* Temporarily disable shared element screens in example app

* Fix card positioning when transitioning

* resolve rnn dep from npm