[ferret_users] Documentation updates, and Hints for searching Ferret documentation

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi all,
We've completed an update to the on-line Ferret Users guide, ../../documentation/users-guide/users-guide.html,
fixing many internal links.  Where you used to see something like (See p.
255),
which was not linked correctly anywhere, you will now see a highlighted
link to the correct section of the manual,  for instance "See
the section on
Modulo Regridding for details."

In addition to documentation's search box, many users find that a
helpful way to find topics in the documentation is to bookmark a link
to the Users Guide Index,
> ../../documentation/users-guide/full-index/index.html
Open the index in your browser, and use the browser's search capability
to look for words.  For instance, if I search for the word average,
I see that there are links to 
> average
>   
>    @AVE regridding
>   
>    monthly climatology
>   
>    over complex regions in space
>   
>    transformation @AVE
>   
>   
>   seasonal averages
>   
>   transformation
>    @AVE average
>   
Happy Ferreting -
Ansley