[Developers] New version of MQL tutorial

[David Flanagan]

Developers,

I've completed a new version of my MQL tutorial, and have made it 
available, in PDF form, here: 
http://www.davidflanagan.com/Metaweb/mqltutorial.pdf

This new version is better organized and more complete than the one that 
is currently available in HTML on freebase.com.  New material includes 
coverage of these MQL features:

- link queries
- reflective queries
- history queries
- the != operator an optional:forbidden directive
- enumerations
- the ! property prefix
- the return:count directive

I'm posting this updated chapter before I update the rest of the book 
because there is so much new material in it.  I hope you find it useful. 
  Your feedback on this draft is most welcome.  Please note that the 
tutorial is Copyright (c) 2008 by Metaweb Technologies, Inc.

	David Flanagan