Comment out warnings

These warnings are very irritating. They do not warn about deprecated or misused feature. They are issued any time you compile the tests. They don't provide any useful information unless you look at the code and have insight in the implementation detains.

To sum up: They don't look like a warning addressed to the user, but like a reminder on an intended future implementation addressed to the implementor. Hence they should not be exposed to the user.

If anyone feels that this is an important user warning feel free to re-enable it after adding enough information making the warning actually useful.

dune/istl/paamg/amg.hh

@@ -325,7 +325,7 @@ namespace Dune
         postSteps_(parms.getNoPostSmoothSteps()), buildHierarchy_(false),
         additive(parms.getAdditive()), coarsesolverconverged(true),
         coarseSmoother_(),
-#warning should category be retrieved from matrices?
+// #warning should category be retrieved from matrices?
         category_(SolverCategory::category(*smoothers_->coarsest())),
         verbosity_(parms.debugLevel())
     {