[cleanup] Unify addCriterion methods.

Now theres only a single addCriterion methods passing all
its arguments to the Criterion constructor (by means of
perfect forwarding).

dune/solvers/solvers/loopsolver.hh

@@ -47,25 +47,6 @@ public:
       */
     virtual void check() const;
 
-
-    /**
-     * \brief Add a convergence criterion
-     *
-     * All criteria are checked after each loop. The solver loop will
-     * terminate once any of the supplied criteria evaluates to true.
-     * If you want to terminate only if several criteria are true
-     * you can combine criteria using the overloaded bitwise
-     * logical operations.
-     *
-     * Besides checking the criterion the LoopSolver will
-     * print the diagnostic string returned by the criterion
-     * in a column with the criterions header string on top.
-     */
-    void addCriterion(const Dune::Solvers::Criterion& criterion)
-    {
-        monitors_.push_back(Dune::Solvers::Criterion(criterion));
-    }
-
     /**
      * \brief Add a convergence criterion
      *
@@ -79,14 +60,14 @@ public:
      * print the diagnostic string returned by the criterion
      * in a column with the criterions header string on top.
      *
-     * This is a convenience method that just forwards all
-     * arguments to the constructor of Dune::Solvers::Criterion.
-     * Refer to the documentation of the latter for details.
+     * This method forward all arguments to the constructor of
+     * Criterion. So you can pass a Criterion or any argument
+     * list supported by the Criterion constructors.
      */
     template<class... Args>
-    void addCriterion(const Args&... args)
+    void addCriterion(Args&&... args)
     {
-        monitors_.push_back(Dune::Solvers::Criterion(args...));
+        monitors_.emplace_back(std::forward<Args>(args)...);
     }
 
     /**