[Bf-docboard] Add a contribute link to the blender manual

[Gaia]

Would it be useful to add a "contribute" link
at a prominent location in the manual ? For example:

http://www.pasteall.org/pic/show.php?id=81986

The "contribute" link could point to a document which
in turn provides some info about:

- the aims of the manual (why it was moved from the wiki)
- how to setup the manual development
- The writers style guide
- where to get help as a manual writer
- ...

So that all is in one place and easily accessible especially
for users who are just stepping in with a fresh mind...

Also would it be useful to update the following page ?

http://www.blender.org/get-involved/documenters/

thanks
Gaia