CSGintro update

[From Dag Forssell (930831 2100)]

Gary, how about substituting this paragraph for the existing
equivalent in our CSGintro: (Occasioned by Bill's comment on my paper).

The PCT paradigm originates in 1927, when an engineer named
Harold Black recognized and clearly described a closed loop
control system as a special kind of mechanism. He was working
with the negative feedback amplifier, which is a control device.
This led to a new engineering discipline and the development
of many purposeful machines. Purposeful machines have built-in
intent to achieve consistent ends by variable means under
changing conditions.

Also, I believe Kent's entry should be modified:

McClelland, Kent. (1993). _An Introduction to Perceptual Control Theory_
and _Perceptual Control, Interpersonal Control and Social Power_.
     Available from the author, Grinnell University, Grinnell, Iowa.

I send this by way of the net, so we can see if it creates any
error signals anywhere.

Best, Dag