ILSGateway, EWSGhana changes

http://manage.dimagi.com/default.asp?148847#837455
http://manage.dimagi.com/default.asp?134684#831319
http://manage.dimagi.com/default.asp?148852#831253
changes in checkpoint according to discussion in google group.  
@czue @twymer
My intention is to use `ObjectProperty` when subclassing `JsonObject` directly, and `SchemaProperty` when subclassing couchdbkit's `Document` or `DocumentSchema`, since that's what it was originally called. So this looks good to me.