Store unhandled command-line arguments.

A new method ParameterGroup::unhandledArguments() is available to
access the list of unhandled arguments. Before, when such arguments
were encountered they were ignored and a warning was printed to
standard out.

Apart from the lack of a (potentially misleading) warning, this
should not change the behaviour of existing clients of the class.

opm/core/utility/parameters/ParameterGroup.cpp

@@ -329,5 +329,10 @@ namespace Opm {
 	    }
 	}
 
+        const std::vector<std::string> ParameterGroup::unhandledArguments() const
+        {
+            return unhandled_arguments_;
+        }
+
     } // namespace parameter
 } // namespace Opm

opm/core/utility/parameters/ParameterGroup.hpp

@@ -267,6 +267,9 @@ namespace Opm {
             /// Insert a new parameter item into the group.
 	    void insertParameter(const std::string& name, const std::string& value);
 
+            /// Unhandled arguments from command line parsing.
+            const std::vector<std::string> unhandledArguments() const;
+
 	private:
 	    typedef std::shared_ptr<ParameterMapItem> data_type;
 	    typedef std::pair<std::string, data_type> pair_type;
@@ -276,6 +279,7 @@ namespace Opm {
 	    map_type map_;
 	    const ParameterGroup* parent_;
 	    bool output_is_enabled_;
+            std::vector<std::string> unhandled_arguments_;
 
 	    template<typename T, class Requirement>
 	    T translate(const pair_type& data, const Requirement& chk) const;

opm/core/utility/parameters/ParameterGroup_impl.hpp

@@ -150,9 +150,7 @@ namespace Opm {
 		} else if (file_type.second == "param") {
 		    this->readParam(files[i]);
 		} else {
-		    std::cout << "WARNING: Ignoring file '"
-                              << files[i] << "' with unknown extension.\n"
-			      << "Valid filename extensions are 'xml' and 'param'.\n";
+                    unhandled_arguments_.push_back(files[i]);
 		}
 	    }
 	    for (int i = 0; i < int(assignments.size()); ++i) {