changed: make StandardWellEquations data members private

use a friend declaration for StandardWellEquationAccess to
give the assembler access to the matrices/vectors.

opm/simulators/wells/StandardWellEquations.hpp

@@ -35,6 +35,7 @@ namespace Opm
 {
 
 class ParallelWellInfo;
+template<class Scalar, int numEq> class StandardWellEquationAccess;
 class WellContributions;
 class WellInterfaceGeneric;
 class WellState;
@@ -123,6 +124,9 @@ public:
         return resWell_;
     }
 
+private:
+    friend class StandardWellEquationAccess<Scalar,numEq>;
+
     // two off-diagonal matrices
     OffDiagMatWell duneB_;
     OffDiagMatWell duneC_;