[authors] Cross-refs in our docs

[Jean Hollis Weber]

Some of our user guide chapters have large numbers of cross-references 
to figures that immediately follow the sentence or paragraph referring 
to them; other chapters have very few x-refs in those situations.

Because x-refs have a tendency to randomly go goofy when chapters are 
combined in a book, I recommend that we avoid using unnecessary 
x-refs. Some are necesary, for example if they refer to a figure on a 
different page, but many really are not needed for clarity. Let's 
purge the unnecessary ones.

--Jean