[w3c/webauthn] 564b70: Markdown cleanup

  Branch: refs/heads/vijaybh/markdown-cleanup
  Home:   https://github.com/w3c/webauthn
  Commit: 564b7003369a0c21a796f37595eb1d2e8b7197ca
      https://github.com/w3c/webauthn/commit/564b7003369a0c21a796f37595eb1d2e8b7197ca
  Author: Vijay Bharadwaj <vijaybh@users.noreply.github.com>
  Date:   2016-04-22 (Fri, 22 Apr 2016)

  Changed paths:
    M index.src.html

  Log Message:
  -----------
  Markdown cleanup

No changes to substance here. Goal of this change is to make the spec
easier to work on, not to fix the content.

- Wrap all lines at 128 chars (wide enough for modern screens, small
enough to fit in most commonly-sized windows)
- Remove extraneous HTML tags
- Convert HTML tags to Markdown equivalents
- Define macros for a couple of commonly used phrases so it's easier to
type and to keep consistency throughout the spec