removed some finished tasks

[[Imported from SVN: r7376]]

TODO

@@ -43,11 +43,8 @@ and maintain.
   store the solution there and make getSol() return this reference
   and no copy.
   (C: I'd prefer the latter to reduce the number of vector copies).
-* Move stuff done in MultigridStep::setNumberOfLevels() into preprocess().
-* Remove MultigridStep::setNumberOfLevels(), this number is already
-  fixed by the size of the transfer operator vector.
-* MultigridStep hides member names from the base class by reusing
-  them for different things
+* Remove deprecated methods MultigridStep::setNumberOfLevels(), setProblem(...,numlevels)
+  constructors with argument numlevels after next release (2.3)
 * Make setting up a MultigridStep easier. E.g. by providing a default
   version that is preconfigured with GS smoother and coarse grid solver.
 * MultigridStep works differently on the finest and the other