GDP: tutorial @seealso links

[Graham Percival]

Hi all,

I updated Learning Manual 2.1.2  to use the same @seealso format as the 
notation reference.  You can see the old method in 2.2.1, and actually 
the rest of the section for now.

I'd like to change all the @seealso sections to match 2.1.2.  Does 
anybody have a huge objection to this?

Cheers,
- Graham