Restricts guest access to user data & fixes photo URLs for WordPress

The user/summary endpoint for WordPress widgets wasn't blockable with the appropriate permission, and  UserQuery was giving up unnecessary data in safe mode. 

This change would cause WordPress user widgets to stop working if Guests do not have the Garden.Profiles.View granted, but I think that would be appropriate in most cases since the desire to restrict user data & that widget are conflicting goals.

I did not find any other uses of UserQuery's 'safe' flag to be broken by the column list change. The WordPress plugin appears to only use Name, UserID, and Photo anyway.

//edit: Added fix for UserModel->GetSummary() which should return parsed Photo urls, not the raw database values.