Add NOT_FOUND to PlaceServiceStatus

Although this status is not documented it is returned by service in some cases. This causes exception when enum constant is parsed in com.google.gwt.maps.client.placeslib.PlacesServiceStatus#fromValue.

Request example 
URL `https://maps.googleapis.com/maps/api/js/PlaceService.GetPlaceDetails?1sCkQyAAAADDrVJSnZJy90R-zu23yOP6nAf7wmpaws0Hmm8_yI9m3TlcJ6df6-7T1ZpZN91Wrusk4Hz50ZHXIyA1Ube81qKhIQFD9dg2uod4VN5kP6TKWwExoU4IbBEMnbinzwFd1hIHHMgmNB0uM&2ssv&callback=_xdc_._guqcne&token=56049`

Response
`_xdc_._guqcne && _xdc_._guqcne( {
   "html_attributions" : [],
   "status" : "NOT_FOUND"
}
 )`