change format of JSON map names so they can be JavaScript identifiers

In Javascript, if you have an hash (map) object in a variable, e.g. "cas", you reference the value of a key using {{ cas["keyname"] }} or, better: {{ cas.keyname }}. For the 2nd form to work, keyname must be a valid Javascript name. Names like @views are not valid. So change these to forms e.g. _views which are valid.