Add methods for getting and setting primary variables.

These can be used to manage state in the well models, and will
be used in the NLDD solver option. Also added the setupDomains()
method, as the getters and setters are working on a domain basis.

opm/simulators/wells/StandardWell.hpp

@@ -253,6 +253,9 @@ namespace Opm
                                     double* connII,
                                     DeferredLogger& deferred_logger) const;
 
+        std::vector<double> getPrimaryVars() const override;
+
+        int setPrimaryVars(std::vector<double>::const_iterator it) override;
 
     protected:
         bool regularize_;