Pause spoken audio like podcast or audio book on iOS, fix build warnings

This build includes a fix for iOS to pause spoken audio like podcast or audio book. Also some empty sub methods have been added to silence the build warnings.

Send "tts-progress" event on Android

Thanks to @liviu-padurariu contribution we now send "tts-progress" events on Android.

Also this release removes peer dependency on "react-native-windows", react-native-windows is still supported, but it won't be required if you're not using it.

React-native-windows support

This release adds support for react-native-windows by @tritao thanks a lot for your contribution!
Also, there is a fix for #172 by @ngocdaothanh thanks!

Bugfix release

Changes from @Sharcoux @guhyeon with fixes to type declarations and java sources.

Harmonise return values in iOS/Android

Changes from @Gyran to make sure that certain API calls return the same values on iOS and Android.
Address deprecation of 'compile' directive in gradle.

Properly resolving promise for calls to setDefaultEngine()

This is a bugfix release addressing issue where the promise from setDefaultEngine() would never resolve.
Thanks to @brunoccc for contribution.

Add support for listing and setting a TTS engine to use on Android

This release adds new API calls to support using multiple TTS engines on Android. Thanks to @Mateus-Brito for PR!

Update to support React Native 0.59

This release features build changes to support ReactNative 0.59 on Android and new API to work with silent switch on IOS. Thanks to @phuongwd and @re7eal for contributions.

Update to support React Native 0.56

React Native 0.56 uses Android 26 SDK. This update changes targetSdkVersion for Android to 26 as well.

Fix crash on Tts.stop and Tts.pause when onWordBoundary=true

This release includes fix by @philharton for EXC_BAD_ACCESS when calling Tts.stop(true).