Update image test following code change
Add travis support
Add controls="controls" when generating <audio> tag
Discard src attribute from audio and video tags

Because we're already using <source> tag
Add controls="controls" in video tags
Only generate autoplay="autoplay" when autoplay is true in cnxml

autoplay="false" causes the audio and video to play automatically
Merge pull request #61 from Connexions/add-travis-and-fixes

Add travis support and fix audio and video tags