Add web support

[BossBele]

WEB SCREENSHOT:

MOBILE SCREENSHOT:

APPROACH

• Converted remaining class component(s) to functional components
• Removed flow dependency in code as it makes the process of transpiling for web and mobile very difficult (requiring babel and webpack), and slows down hot reloading in react native to the point where the app timeouts.

• Added modal component for web modal-react-native-web which works perfectly.

  Open to suggestions from the community if it is found that flowjs is neccessary.

[AndreiCalazans]

I appreciate the PR but it's not in my intention to extend this library to support web. Feel free to fork it and use your own version. Thank you for understanding.