Announce Quattor 13.6.
Adjust the <base> tag for local testing.

With new versions of jekyll, it was requesting images and CSSs on
locations relative to the document being displayed, which was wrong.
Adapt the README to newer versions of Jekyll.
Merge pull request #36 from piojo/quattor-13.6

Announce Quattor 13.6
Merge pull request #35 from piojo/readme-fix

Adapt the README to newer versions of Jekyll.
Announce the newest stable release.
Merge pull request #37 from piojo/quattor-13.1.1

Announce 13.1.1
Fix typo.
Merge pull request #38 from piojo/quattor-13.1.1

Fix typo in the announcement of 13.1.1