Jest transform support / documentation

Hi, thanks for the awesome library. Nice to see proper TypeScript support in React Native.

As Jest is the default test runner in React Native projects created by by the `react-native` cli tool, it would be nice to see support or documentation on how to use this library as the transformer for Jest as well.

Of course the alternative is to use [`https://github.com/lozinsky/typescript-babel-jest`](https://github.com/lozinsky/https://github.com/lozinsky/typescript-babel-jest), but would somehow be nice to use the same transformation for tests and production.