groups/comps dtd

Hi All,
 I made up a groups.dtd that more or less matches up with the comps.xml
format.

Changes:
 - <groupreq> inside <grouplist> is dropped for adding a 'mandatory'
'type' attribute to the <metapkg> element.
 - I have not included the <grouphierarchy> sections - not sure what the
purpose of these sections entirely would be for repository group data.

questions:
 - not sure what the default element is for
 - should type for metapkg and groupreq be enumerated?
 - 'uservisible' and maybe 'default' should be attributes to the <group>
tag?

http://linux.duke.edu/~skvidal/metadata/groups.dtd

Thanks,
-sv