Add button that adds a video to timeline as an attachment

Adds a button to index.jsp to add "A video", and updates the main servlet to actually insert the video into the timeline as an attachment, includes two new static files, an image and a video.  

A note on contribution guidelines - I shot the video and am happy to license it however, and I submitted my CLA this evening, so that should be ready soon.

This is related to this Stack Overflow question: http://stackoverflow.com/questions/16866516/how-to-play-an-attachment-video-from-the-timeline-item