First cut at cookie support for ZServer FTP server. This is needed for things like FTP authentication via UserDB.

changes to them after initial creation were lost :(

implements coordination of Zope and external transaction managers.

coordination of Zope and external transaction managers.  See the
gadfly DA (class DB in db.py) for an example of use.

fail in some cases when it shouldn't in ZServer.

manage_tabs should really be a Python method.  It's just too complex.

an attribute?

exclude tabs it can't find. (Does this hurt anything?)

causes caching problems with clients :(

problems with some clients.

defined for previously existing installations that may have added roles
in the top-level folder.

manage_setLocalRoles. The calls were used to try to ensure
that one could not set local roles that are not defined in
the installation, but that can cause failures when trying to
import folders from other sites.

the way Python does them.  In particular, we we has a "0x" prefix on
the address part that Python strips off.  This has to be fixed
so that Zope's detection of non-content would work.