[Dune] Grid Documentation

[Christian Engwer]

Hi,

I'm working on a reorganisation of the Grid Documentation.

Please have a look at 
http://hal.iwr.uni-heidelberg.de/~christi/dune/modules.html
and let me know what you think of the structure. There is a top level
group Grid with Sections for the "Grid Developer API" ( for Adrian ;-) ),
the "Grid Application API" ( for all the people using a grid ) and a
list of all implementations containing there specific Documentation.

CU Christian