catch whereisKey exception and provide error messages when external programs neglect to

catch whereisKey exception and provide error messages when external programs neglect to

* whereis: If a remote fails to report on urls where a key
  is located, display a warning, rather than giving up and not displaying
  any information.
* When external special remotes fail but neglect to provide an error
  message, say what request failed, which is better than displaying an
  empty error message to the user.