CYB-217 Enable detailed view & allow videos to be played
https://jira.ets.berkeley.edu/jira/browse/CYB-217

* Rename attachments table's field url to image_url
* Add a service to get video metadata
* Add video data (stored in the media_urls table)
* Modifies attachments_processor for the renamed attachments field
CYB-217 Enable detailed view & allow videos to be played
https://jira.ets.berkeley.edu/jira/browse/CYB-217

Work by @christianv toward Gallery Display
Merge pull request #108 from coyote/videos_in_gallery_api

CYB-217 Enable detailed view & allow videos to be played