Fix html5shiv and respond urls.

Use the same as the Bootstrap docs and thus fix page display with IE < 9.
Enforce unix line endings like the Bootstrap repository.
Update Bootstrap to v3.0.3.
Use the non-www link.
Compress images with kraken.io.

Savings: 723.36 KB.
Specify <meta http-equiv="X-UA-Compatible" content="IE=edge">.
Update _config.yml.

Disable pygments since no code highlighting is used.
Also exclude README.md from the out dir.
Fix validation errors.
Remove `type="text/javascript"` since it's the default.
Remove the unused _includes/colophon.html.
Use the https links for github and Twitter.
Move stuff that belong to the footer to footer.html.
Remove empty selector and media query.
Clean up .gitignore.