EML

The current set of DTD files checked into the eml module do not correspond in a
1:1 way with the XSD files. In particular, 1) parameter entities were resolved
(e.g., eml-dataset includes eml-resource) and should not be; and 2) multiple
global elements in the schema should be represented as possible root elements in
the DTD but in fact were eliminated. For example, in eml-entity, both
"table-entity" and "other-entity" should be root elements in the eml-entity.dtd,
but infact only "table-entity" is present because it caused some problems
withthe software we were using to parse DTDs. This needs to be fixed so that
all appropriate elements are available.