new directory access semantics implemented

[Alexey M. <al...@hs...>]

I've implemented directory semantics described in the corresponding
chapter of acl-rfc.txt (which I posted here yesterday).


The only thing that was incorrectly stated:

 - proposal was talking about "directory without ACLs at all";

 - it should really talk about "directory without an ACE (Access
   Control Entry) for the user in question;


That way, the repository policy gets used correctly, and all tests
still pass (except for the

  9: acl.at:338        FAILED near `acl.at:353'

which I'll fix shortly (it has to do with CVSROOT/default-deny, which
is not yet implemented).

--alexm