DDS15 — Deprecated usage of IDL in the DDS spec

The CORBA specification (08-01-04) in section 7.11.6 deprecates the use of anonymous types, for example the type of the struct field "seq" below:
struct Foo

;

The DDS DCPS IDL uses these in multiple places (the first is DDS::UserDataQosPolicy). These should be replaced with non-deprecated usage such as:
typedef sequence<octet> OctetSeq;
struct Foo

;

This will also increase internal consistency of the DDS spec, since it already uses a DDS::StringSeq typedef in the PartitionQosPolicy struct.

Furthermore, if the element type of the sequence is a Basic Type or a String Type, the CORBA module already provides these typedefs, so it would be preferable to use them. The example above becomes:
struct Foo

;