[js] Add React.Ref support to captureRef

Fix dependency incompatibility

Fix index.d.ts import from react-native types

Old config called `Android dependency 'com.android.support:support-v4' has different version for the compile (26.1.0) and runtime (27.1.1) classpath. You should manually set the same version via DependencyResolution` error, this PR has fixed this

Fix flow types

add capture() definition to index.d.ts

fixed bug with child views transformation loss

Android performance improvements

Fixed the compile error

extension is final and cannot be changed.

fixed the base64 MIME type when JPG is chosen (iOS)

Merge from gre/react-native-view-shot

fixed the base64 MIME type when JPG is chosen

close java OutputStreams before resolve Promises

add null check

Add type definitions for style prop

 fixed the base64 MIME type when JPG is chosen

valid MIME type for JPEG / JPG images is "image/jpeg" 
https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types#Image_types
This was causing Android not to recognize the screenshots taken by this library

Fix psitioning of TextureView elements relative to target element

Remove .iml file and add rule to npm and git ignore

Adding style props to main container.