Subproject documentation

[Richard S. Hall]

I just wanted to let people know that I have created a new "Subproject 
Documentation" page on our "documentation" page; this can be the root 
for all subproject documentation.

I have moved the existing subproject documentation to this page. To 
start documenting your subproject, simply add a child page to the 
"Subproject Documentation" page and it will automatically appear on the 
generated web page.

-> richard