[w3c/webauthn] 212de8: Clean up attestation

  Branch: refs/heads/vgb-modular-attestation
  Home:   https://github.com/w3c/webauthn
  Commit: 212de84c2a54ecefddcaa3138e2ef67e47f8dd7e
      https://github.com/w3c/webauthn/commit/212de84c2a54ecefddcaa3138e2ef67e47f8dd7e
  Author: Vijay Bharadwaj <vijaybh@users.noreply.github.com>
  Date:   2016-08-10 (Wed, 10 Aug 2016)

  Changed paths:
    M img/fido-signature-formats-figure1.svg
    M index.bs

  Log Message:
  -----------
  Clean up attestation

- Standardize the authenticator data so all formats have equal support
for AAGUID, extensions, etc. This also removes a lot of duplication
across structures.
- Add structure to the definition of attestation formats. Fixes #126.
Fixes #127.
- Simplify the naming of the attestation types to make it easier to
understand
- Clean up mentions of GUID. Fixes #148, fixes #149, fixes #150.
- Clarifies how to use self attestation. Fixes #115.
- More detailed pointers on how to generate a TPM attestation.
- Simplify Android attestation to remove fields that were not really
attested by authenticator and were therefore creating a false sense of
assurance.