The timer for the cpu time (wall time) in run() method is now acessible from...

The timer for the cpu time (wall time) in run() method is now acessible from outside (i.e. from problem) via an access function wallTime()

git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@6943 2fb0f335-1f38-0410-981e-8018bf24f1b0