[om-list] tutorial, and demo updates

[luke call]

Using suggestions from the recent discussions on soylentnews.org:
   https://soylentnews.org/article.pl?sid=16/04/23/0149257

..., I added a tutorial to the web site.  It is linked in the "FREE 
DEMO" page and the Documentation page.  I also added other introductory 
content (what it does, architecture), under "More about OM" then 
"Features, limitations, internals", and then "internals".

   tutorial:  http://onemodel.org/1/e-9223372036854612053.html
   features:  http://onemodel.org/1/e-9223372036854618107.html
   internals/architecture stuff:
         http://onemodel.org/1/e-9223372036854618069.html

I also made the (telnet) demo instance of OneModel look better with an 
80-column terminal (not perfect but better), simplified a bit, and added 
a reference to the tutorial.  This included changing some OM menu text 
lines, to fit better.

Comments & suggestions appreciated, as always.

-- 
Luke A. Call
--------------------------------------
- Things I'd like to say to more people:  http://lukecall.net