CORBA35 — Add optional/map mapping (and other IDL4 special types)

For IDl4 the CDR marshaling should be described, optional could be described as a union with a boolean discriminant, with TRUE containing the value, map as a sequence of structs containing each key/value, other IDL4 extensions can also be described using IDL base types marshaling. That also enables interoperability of optional/map/others with an old implementation without IDL4 support, the IDL has to be rewritten to work, but at that moment an IDL3 app can talk with a IDL4 app (at least for CDR)