Renamed res.locals.public to res.locals.exposed, and added exposed.public (which gets populated from the second argument in res.view) and exposed.private (which is for debugging--populated from the first argument in res.view).
Only expose private variables if in development environment.
Allow any type of data to be sent to the exposed public variable, and now that it is namespaced as exposed.public there is no need to use a loop to extend public--we can just set it outright.