New minor mode Return Indents

[Mark J. Dulcey <Dulcey at MIT-AI>]

I have made some changes (as of 85.19) to the command Indent New Line
(the function normally found on Line).

1.  The variables Indent New Line New Line Function and 
    Indent New Line Indent Function control how the Indent New Line
    function works.  If they are NIL (the default) Indent New Line performs
    the function placed on Return, then the function placed on Line (just
    like before).  If either is not NIL, the command named is executed
    instead.  Among other things, this allows Indent New Line to be
    placed on the Return key without causing infinite recursion.

2.  The new minor mode Return Indents Mode makes it easy to set up your
    ZMACS to cause the Return key to indent the new line (like the default
    definition of Line), and to put the normal definition of Return on Line
    (so you don't lose it altogether).  This wins (at least I think so) in
    Lisp Mode, and loses horribly in Text Mode.  It probably also wins in
    other programming language modes (but I haven't tried it).

This supersedes my previous announcement about a file to allow this in
LMLIB;.  That file is now considered obsolete and will go away soon.