group dzi's into json

[johnwalker]

earlier we talked about using json as a format for specifying collections of dzis. we need to do that before we can address #7 . Unfortunately, this part has to be done by hand since the documents have a very complex naming scheme.

[stephenrparsons]

Script is in scripts directory. The chad3json.py script should be run from the images directory. chad.json is stored in data directory. Closing #9

[johnwalker]

awesome