Extracted configuration of *when* to write restart

The configuration of when to write restart files is quite complex,
involving at least the three keywords RPTSOL, RPTRST and RPTSCHED. This
commit moves that configuration from the IOConfig class to the
RestartConfig class.

At a later stage the RestartConfgig class will be extended with
information of *what* to save in the restart file.

opm/parser/eclipse/EclipseState/IOConfig/IOConfig.hpp

@@ -159,6 +159,8 @@ namespace Opm {
 
         bool initOnly() const;
         const RestartConfig& restartConfig() const;
+        void initFirstRFTOutput(const Schedule& schedule);
+
 
         // Proxy methods forwarding directly to corresponding RestartConfig
         bool getWriteRestartFile(size_t timestep) const;
@@ -191,7 +193,6 @@ namespace Opm {
                   bool nosim,
                   const std::string& input_path );
 
-        void initFirstRFTOutput(const Schedule& schedule);
     };