Renamed initStateTwophaseFromDeck() -> initStateFromDeck().

- Made initStateFromDeck() into a template taking arbitrary properties.
Implementation detail:
  - initWaterOilContact() was also templatized on props.
  - initHydrostaticPressure() is now overloaded on prop interface types.

examples/wells_example.cpp

@@ -58,7 +58,7 @@ int main(int argc, char** argv)
 
     Opm::TwophaseState state;
 
-    initStateTwophaseFromDeck(*grid.c_grid(), incomp_properties, parser, gravity[2], state);
+    initStateFromDeck(*grid.c_grid(), incomp_properties, parser, gravity[2], state);
 
     // Compute phase mobilities
     std::vector<double> phase_mob;