LOOP iteration macro

[JONL at MIT-MC (Jon L White)]

About a month ago we talked about the possibility of making LOOP
be autoloadable -- the one hitch being the state of controversy
over the "FOR" keyword (whether it should defaultly initiate a 
LOOP too).  Just saw WAM and PSZ now, and it seems that the safe
and right thing to do now is to install an autoload property for
LOOP, have the symbol FOR around so that later we can later patch
an autoload in for it.  And at least in the forthcoming LISP RECENT
we can announce LOOP and its documentation.