react and d3 integration

[david-trumid]

• Renamed react files to .jsx
• Added very basic listing (babel with eslint) - just remove the .eslintrc.json file to turn it off (I recommend keeping it)
• Made a helpers file to keep some common functions
• Made BasicScalarEncoder (along side SimpleScalarEncoder so you can see old/new code if you want, I only reference BasicScalarEncode now in page)
• Made a scrubbers folder to hold scrubber components (only did one for number - using hooks to show you an example of how you don’t need a React.Component just to use state)
  -- There is something wrong with the way the d3 is handling dragging (didn’t investigate too far though), I recommend just using something like dat.gui. Code is in Number.jsx
  --- I added a little section at top of page to show you an example (with all the changeable params)..you can remove it

Some suggestions..

• Name files .jsx if it contains react components
• Import React on first line
• Add prop types if you can (I just use TypeScript which supports type checking and no need for prop types - but that is a bigger change)
• Use object structuring if you can
• Use const instead of let unless the value or reference will change

[david-trumid]

feel free to change the tab/spacing didnt want to dig too deep into formatting and just let the linter style it