Automatically building, testing and deploying-the docs with travis and github-pages

[bakaniko]

I found this link recently about automaticly build and deploy webpages using travis and github-pages:

​https://nathaneastwood.github.io/2017/05/16/automatically-building-testing-and-deploying-bookdown-with-travis-and-github-pages/

I think we can build in our github repo a more up to date documentation for our contributors

It can be triggered when we merge. In that way, people won't have to wait the next release.

Plus we can build more artifacts like doc bundles for the liveDVD and a presentation archive for our speakers.

• Webpages
• debian package
• presentation bundle

[darkblueb]

docs now built as a dot-deb, thx johanvdw