[Dune] read vs. operator[]

[Oliver Sander]

Hi there!
In two classes there existed a method read() for read-only-access
to some class members.  I have replaced those with operator[] const.
Code using these methods may not compile anymore.  Please apply
changes accordingly.

--
Oliver

************************************************************************
* Oliver Sander                **                                      *
* Freie Universität Berlin     ** email: sander at math.fu-berlin.de      *
* Institut für Mathematik II   ** phone: + 49 (30) 838 75217           *
* Arnimallee 2-6               ** fax  : + 49 (30) 838 54977           *
* 14195 Berlin, Germany        ** URL  : www.math.fu-berlin.de/~sander *
************************************************************************