[authors] Writer Guide Ch 3 (Working with Text): new section added

[Jean Hollis Weber]

I have added a new section at the end of WG Ch3 (Working with text), about 
using hyperlinks and cross-references. I used change tracking. The file is 
here:
http://oooauthors.org/en/authors/userguide2/writer/feedback/0203WG-WorkingWithText_27Oct07_JHW.odt
I've submitted it for review. Feel free to review the whole chapter, but 
please concentrate on the new material.

Peter: over to you for replacement illustrations as needed.

--Jean