React Stars cleanup

[kayluhb]

• Take advantage of React's defaultProps
• Use props instead of state.config since state should only hold things that change
• Fix validation issues with changing state on component mount
• Fix prop-types import for React 16+
• Don't use a cursor if when you cannot edit
• Don't chain variable assignment
• Don't reassign parameters
• Don't bind methods in the render
• Don't call methods when not editing
• Add all propTypes to the propTypes declaration
• Add a displayName attribute for easier debugging

[olegberman]

Thank you @kayluhb! Can you double check what happened to examples? This is what I am getting after building

[olegberman]

Apologies, that was my fault by running examples from local file://. That is fixed in e91448d. I checked out at your latest commit 9b4dfd9 I am getting an issue with half stars. You can try yourself (run npm run dev-example and try second example).

[kayluhb]

@olegberman rebased with master and fixed the issue. If I get a chance I'll submit a new PR for running some jest tests.