XMI12 — DTD productions for names of Classes in nested Packages

There is an inconsistency between the EBNF and pseudocode that
generates DTD element declarations for Classes. According to
the EBNF (production 6a) the element name is the "name of Class"
preceded by an optional namespace. According to the EBNF, the
element name is a the qualified Class name.

There are two issues:

1) If we follow the EBNF and use an unqualified name, there is
a risk of name collision when there are Classes in nested Packages.

2) If we follow the pseudo-code, we lose the namespace prefix.

see above