[w3c/webauthn] ce6a90: Rename imageUri to imageURL

  Branch: refs/heads/vijaybh/59-imageUri
  Home:   https://github.com/w3c/webauthn
  Commit: ce6a9046409c1147506752916c5bc47df48c530b
      https://github.com/w3c/webauthn/commit/ce6a9046409c1147506752916c5bc47df48c530b
  Author: Vijay Bharadwaj <vijaybh@users.noreply.github.com>
  Date:   2016-04-12 (Tue, 12 Apr 2016)

  Changed paths:
    M index.src.html

  Log Message:
  -----------
  Rename imageUri to imageURL

Also removed the level from the metadata since it was appending a 1 to
the document title. Fixes #59. I decided not to mandate manifest
formatting of the icon to avoid the added complexity. Authenticators
would have to implement it, and we'd have to explore all the things a
bad person could do (e.g. have very different looking avatars at
different resolutions).