#44 better UNDO, return in outlines

[PreFab Software]

Frontier's undo is a bit limited, e.g. in an outline, hitting return starts a
new undo buffer (or whatever it's called internally) so it's impossible to
undo prior to the return. That might be ok if the return was
intentional, but is frustrating when I accidently hit the return key in the
middle of typing something.

multiple levels of undo might be hard in the general case, but perhaps
there's a simpler fix for textual changes in an outline (or script of
course)