- Fixes: https://github.com/beefe/react-native-picker/issues/248

Allow user to specify row height for iOS

fix crash

add requires main queue setup

Try compatible  miui

Update PickerViewModule.java

ios: do not show picker at the end of initialising

Fix import in header for RN48 compatibility. see #208 

去除Dialog的TYPE_TOAST样式，去除对悬浮窗口权限的依赖

新增iOS picker在滚动中禁用确定按钮事件 防止选择的数据错乱

Remove createJSModules - RN 0.47 compatibility

Make it possible to integration with an existing ios app

修复android与ios使用中遇到的bug

Return selected index if returned selected array is empty

With the file, we can integrate `react-native-picker` with an exist native `iOS` project like bellow:
``` ruby
// Podfile
pod 'Picker', :path => '../YeSanPoRN/node_modules/react-native-picker'
```

Added typescript typings