Merge pull request #23 from freeranger/v2.0.0

• Updated to React 16.13.1
• UNSAFE_componentWillReceiveProps replaced with getDerivedStateFromProps
• All packages updated
• All tests passing

v1.0.3

• Rename componentWillReceiveProps to UNSAFA_componentWillReceiveProps - see https://reactjs.org/blog/2018/03/27/update-on-async-rendering.html
• Fix ESLint failure

Migrate to PropTypes

React has pulled prop types out into a separate package.
This release simply uses that package.

Version 1

Added the ability to specify custom styles for and elements