[eigen] A modest start with the documentation

[Jitse Niesen <jitse@xxxxxxxxxxxxxxxxx>]

Hello,

I had a quick go at the 5-minute "Getting Started" guide yesterday. For 
the moment, I uploaded the result at
   http://www.amsta.leeds.ac.uk/~jitse/eigen/GettingStarted.html

Motivation:
* I tried to keep it as short as possible
* Avoid common mistakes (so I include <Eigen/Dense> )
* I only use MatrixXd because I think that's enough for many applications
* I think the current tutorial assumes a too sophisticated audience; my
  page is thus much simpler (perhaps too simple?)

Any comments?

I also took Benoit's email and some other sources and produced an outline 
of the documentation that we should / could write on the wiki:
   http://eigen.tuxfamily.org/index.php?title=Documentation_for_Eigen3
I hope that this helps us with planning and organization. If you have 
ideas please jot them down there.

Cheers,
Jitse