Consolidation: add package-internal class as place-holders for GeoAPI interfaces not yet standardized.
The intend is to allow us to write the code in a way that anticipate the fact that Attributes will not
be the only kind of Properties in a Feature (other properties will be Associations and Operations).


git-svn-id: https://svn.apache.org/repos/asf/sis/branches/JDK8@1593420 13f79535-47bb-0310-9956-ffa450edef68