Update to latest source

List of changes cherry-picked from master:
Chris Harvey (2):
      replace div.sr-only with img alt attribute
      correct nav menu side

Forbes Lindesay (1):
      Document `globals` option

Timothy Gu (2):
      Fix link to Travis CI and GitHub repo
      layout: Remove commented out cruft

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Merge pull request #1724 from TimothyGu/gh-pages

Update to latest source