Finish change active # of devices

Fill in the blanks from Marks' set active devices.

Handle vectors as well as addresses.

Allow set autoconfig on non-PDP10s.  (Are there any?)

Disable DISABLE for units.

Disallow changing active devices when devices ARE active.  Defined as
any DUP is owned by a KMC.

Changed the device name to KDP for consistency with DECnet docs and
commands.