Add support for the new webhooks event for installations. See: https://developer.github.com/early-access/integrations/webhooks/ Closes #434. Change-Id: I74d3d50cb6b350322fc4515ad70097f0f70ae478
Closes #427. Change-Id: I67faac8df63e0d55fcce4ca5f9ab50e26c04d6b3
Fixes #361. Change-Id: I1c80b8eb7816efc9b83e6b8be956430c68809d5e