XMI12 — Completeness of TypeCode and Any support

The "fixed elements" for XMI.CorbaTypeCode in sections 6.5.18 & 7.5 are buggy.
There is no element for the "unsigned long long" TypeCode, and the element
for the "fixed" TypeCode is not allowed in XMI.CorbaTypeCode.

In addition, we should consider extending XMI's support of TypeCodes and
Anys to cover the "value" types added in CORBA 2.3. [We don't need to
handle Attributes with "value" types at this stage because MOF doesn't
support this in meta-models.]

Editorial: The "fixed" DataType DTD elements appear BOTH in section
6.5.18 and in section 7.5. Could we replace the former with a reference
to the latter?

Close with no action because of updates to MOF 1.4 datatypes