host via github pages

[jonathanong]

because webtester.mraid.org does not support HTTPS. just move master to gh-pages, set it as the default branch, and remove the master branch.

[neiltron]

This is possible now without the branch gymnastics. You can go to the admin settings for the repo under the Github Pages section and changes Source to "master branch".

https://help.github.com/articles/configuring-a-publishing-source-for-github-pages/