Add org.json, members.json, invitations.json for full org download

This allows knife upload / and knife download / to download and upload the organization record (with full name), the list of members, and the list of invitations, which rounds out organization support so that *all* data within an organization can be manipulated by knife diff, upload, download, list, show and delete.
minimize()'s job is to eliminate all keys from the hash that are == to the default.  But we don't want to do that with "name" just because it's nice to have around :)  Better names, comments, all welcome--not sure how to make it nicer but I agree it's not nice the way it is.