Changes

#Retrieve the list of all installed apps, returns an array of app records.<br>#Modify an app record, disallow deleting an app (a user never unpurchases an app but may choose to uninstall it which is denoted by marking it as such in the app record).<br> In addition, there are a few use-cases for aggregate data, not per-user: #Retrieve the number of installs of a particular app (without leaking information about users who have the app installed). Ideally this aggregation would be done by the Sauropod on the server side.#Retrieve general statistics such as: installs/hour and uninstalls/hour.