Use the Map approach in AbstractIdentifiedType for allowing extension with new properties in the future.
This is the same approach than AbstractIdentifiedObject. We will provide a builder in next SIS version
for making construction easier, similar to the ParameterBuilder we just experimented.


git-svn-id: https://svn.apache.org/repos/asf/sis/branches/JDK7@1574852 13f79535-47bb-0310-9956-ffa450edef68