draft of ttk styles tutorial chapter

[Mark Roseman]

If anyone has a chance to look at it, there's now a complete first cut
of the tutorial chapter on ttk styles up at:
http://www.tkdocs.com/tutorial/styles.html

To say that this one has been a learning experience for me is an
understatement. I'm sure there are errors, omissions, or areas that
are unclear or otherwise deficient. Any corrections, enhancements or
feedback would be most definitely appreciated.

Thanks
Mark