[w3c/webauthn] 4f989b: Editorial refactor of spec (#73)

  Branch: refs/heads/vijaybh/markdown-cleanup
  Home:   https://github.com/w3c/webauthn
  Commit: 4f989be18c1444f602c1ef97d339d1f7a5638fda
      https://github.com/w3c/webauthn/commit/4f989be18c1444f602c1ef97d339d1f7a5638fda
  Author: Vijay Bharadwaj <vijaybh@users.noreply.github.com>
  Date:   2016-04-20 (Wed, 20 Apr 2016)

  Changed paths:
    M index.src.html

  Log Message:
  -----------
  Editorial refactor of spec (#73)

Initial proposal for how the spec could be organized to address #1.
Fixes #7, #9. I also removed text that was duplicated across signature
and attestation sections, and added some minimal glue in its place.

I also removed some bikeshed warnings (which could be seen in the
previous version by running bikeshed with the --debug option).

I have some more cleanups I would like to discuss, but would like to get
agreement on this direction first. If agreed, I will add whitespace
cleanups in a separate commit before merging to master.