DataDictionary.readFromURL glitch when Java security policy restricts file system access

readFromURL() tries the passed value as a file before it tries it as a resource. If there is a Java security policy enabled that restricts access to the file system, new FileInputStream() may throw AccessControlException, as opposed to the FileNotFoundException that is caught.

As a workaround, we converted the resource name to a URL before calling the method. (URL is tried before file.)