WIP: Update programmer webpage

[adamwolf]

• Remove TODOs from README
• Use flexbox, grid for the layout
• Remove all floats
• Design for and test on small screens
• Try requestAnimationFrame instead of setTimeout
• Adjust text, visual design
  • Put troubleshooting inside details or something
• Maybe pull the images for LED and use background color on round divs instead?
• Add more pixel mode tests
  • multiple messages
  • mixed pixel and text messages
  • all the pixel options
  • delete some lines of LEDs, add some lines
  • make sure the clicked pixels are "on" and the others are off
• Test on a real Blinky

Maybe:

• split into POV/GRID versions
  • Remove text and options only applicable for one
  • we could use the same code for both, look at the URL or something?
• store programming data in an url parameter
  • we'd have to be able to parse the programming data and populate the UI from it
  • push to history when they add/remove messages?
  • add "share"?
• Improve programming UX
  • show a grid/pov lined up with the boxes?
  • illustrate how the LED should blink
  • explain how to get it to where it needs to be
• Turn into an installable PWA that works offline
• Switch from alerts to html dialogs?
• What do we get with the current drag and drop library? Should we just go with DOM drag and drop now?