Thanks to Michael Sersen for creating images/Logo.svg.

- Add images directory with original SVG logo, favicon, and some
  derivative PNGs of the logo for different purpose.

- Note that license on images/* is CC BY-SA.

- Add utils/img2js.py to take an image and generate a base64 encoded
  data URI string.

- Add base64 encoded data URI screen logo to display in canvas when
  disconnected.