Add the CREATOR utility and wire it into the DOS tools build and NET
command dispatch.
Extend the client-side NCP helpers with the calls needed by the new and
updated tools, including DOS namespace information and effective-rights
queries. Also update MAP handling for automatic drive mappings used by
the login script.
This commit contains the tool/source support only. The DOS baseline test
suite is kept separate and will be added in a follow-up commit.
