r7059: Use namespaces for pidl and the build system, so we can later on

r7059: Use namespaces for pidl and the build system, so we can later on
call out to the build system to compile the various pidl tests
(without having to rely on shared library support).

Initial work on an ndr_array test.
(This used to be commit 2b08c4b92b4f56180c123a502bdcc6c40188c07f)