Replaced SimulatorState -> SimulationDatacontainer

Have removed the SimulatorState base class, and instead replaced with
the SimulationDatacontainer class from opm-common. The SimulatorState
objects were typcially created with a default constructor, and then
explicitly initialized with a SimulatorState::init() method. For the
SimulationDataContainer RAII is employed; the init( ) has been removed -
and there is no default constructor.

examples/wells_example.cpp

@@ -76,7 +76,7 @@ try
         all_cells.push_back(i);
     }
 
-    Opm::TwophaseState state;
+    Opm::TwophaseState state( grid.c_grid()->number_of_cells , grid.c_grid()->number_of_faces );
 
     initStateFromDeck(*grid.c_grid(), incomp_properties, deck, gravity[2], state);