Resolves Issue #6: Unique ID for Marker DIVs
  - Added a MARKER_ID_DELIMITER constant
  - Set the ID of the marker element to a concatenation of the ID of the
video_wrapper element, the delimiter above, and the array index
  - Changed the mouseover and click events to parse the element for the
index using the above delimiter
Merge pull request #7 from AlfrescoLabs/master

Resolves Issue #6: Unique ID for Marker DIVs