Initial, very very hacky, zcml-for-scripts support.  Also, got rid of vestigal principals.zcml.
Patches applied:

 * steve.alexander@canonical.com/launchpad--devel--0--patch-364
   refuel

 * steve.alexander@canonical.com/launchpad--devel--0--patch-365
   removed principals.zcml, as we don't use it any more.

 * steve.alexander@canonical.com/launchpad--devel--0--patch-366
   Work around zope/python insanity where it sticks sys.argv[1] into request.form sometimes.

 * steve.alexander@canonical.com/launchpad--devel--0--patch-367
   added initial and very hackish support for using utilities and adapters from scripts.

 * steve.alexander@canonical.com/launchpad--devel--0--patch-368
   Use a PermissiveSecurityPolicy for scripts.  Make zcml for scripts start an interaction.

 * steve.alexander@canonical.com/launchpad--devel--0--patch-369
   removed references to principals.zcml

 * steve.alexander@canonical.com/launchpad--devel--0--patch-370
   merge from rf

 * steve.alexander@canonical.com/launchpad--devel--0--patch-371
   made ftesting.zcml include the includes excluded from zopeapp.zcml.