SYSKEY, TNG freeze, 2.0.x->TNG merge and other thoughts

[Luke Kenneth Casson Leighton]

> on who the authenticated user is _nd_ depending on the info level being
> requested _and_ depending on wherether it's a write request
> (samr_set_userinfo) or a read request (samr_get_userinfo).

[this is a simplifcation.  it's possible to have create rights and read
rights on a user-object, thereby allowing a user to change their password
(create rights), read their profile (on login), but not delete
themselves].