Create Badge Class List Endpoint to Register with Directory

[kayaelle]

Example:
https://github.com/mozilla/openbadges-directory/blob/master/examples/badges-example.json

Need one for the backpack too. 1.0 badges only. Can make a separate issue for backpack if needed.

Thanks!

[cmcavoy]

Updated example of the format is at http://mozilla.github.io/openbadges-directory/#addbadges