Cleaned up Travis CI configuration file.
Cleaned up Travis CI configuration file.

This commit clarifies certain comments, uses more idiomatic syntax, and
updates the email address for the Travis CI configuration file.

Signed-off-by: Jacob Howard <f862f167b85d41b225785c70d70808bc7337c1fe@havoc.io>

havoc-io/mutagen,havoc-io/mutagen