Merge pull request datacarpentry#246 from datacarpentry/stable-release

move lesson beta -> stable

Merge pull request datacarpentry#139 from rgaiacs/improve-wording

Improve wording on syllabus.html

Merge pull request datacarpentry#138 from swcarpentry/revert-129-dt-ids

Revert "ensure dt elements have an id set"

Merge pull request datacarpentry#137 from rgaiacs/styles-numbering

Numbering the lessons in the schedule