Teaching `auth` how to speak Travis CI
Also teaching auth how to speak GitHub
change github header to X_HUB_SIGNATURE
Merge pull request #1 from colegleason/travis-auth

change Github auth header to X_HUB_SIGNATURE
github: change header to X-Hub-Signature
Merge pull request #2 from colegleason/travis-auth

Change Github header to X-Hub-Signature