switch github pages to master branch

[pkra]

It's a pain to keep in sync with master, now we can switch, https://help.github.com/articles/configuring-a-publishing-source-for-github-pages/.

It takes a bit of work updating the readme etc.

[pkra]

After #199, I've changed the settings so that github.io is now using the master branch.

Leftovers:

• update Readme (in particular link, to documentation page).
• delete gh-pages branch.

[pkra]

@zorkow there's another set of slides only on gh-pages. Are these worth preserving in master?

[zorkow]

That the AHG slides? Yes, I think they are worth preserving. They give a hands-on description how to integrate MathJax/A11Y into web pages.

[zorkow]

I might even have the solutions for the exercise somewhere. I can look for that and update the slides.

[pkra]

Thanks, Volker.

[pkra]

I've deleted the gh-pages branch which is the final piece for this.