Allow elements from other namespaces in the info
elements. Info should be allowed to contain additional
elements from any other namespace with the processing
expectation that they are not used for rendering.
This change will allow markup from other standards to
be more easily associated with content, without having
to be formalized in DocBook. Examples of this would
include Dublin Core metadata (DCMI), Open Digital
Rights Language (ODRL), IMS LOM, etc.
Modules could be easily developed to allow inclusion of