Merge branch 'feature/move-output-operator-to-Dune-namespace' into 'master'

move output operator to `Dune` namespace

See merge request core/dune-common!421

dune/common/parallel/interface.hh

@@ -504,13 +504,10 @@ namespace Dune
     free();
   }
   /** @} */
-}
 
-namespace std
-{
-  inline ostream& operator<<(ostream& os, const Dune::Interface& interface)
+  inline std::ostream& operator<<(std::ostream& os, const Interface& interface)
   {
-    typedef Dune::Interface::InformationMap InfoMap;
+    typedef Interface::InformationMap InfoMap;
     typedef InfoMap::const_iterator Iter;
     for(Iter i=interface.interfaces().begin(), end = interface.interfaces().end();
         i!=end; ++i)
@@ -525,7 +522,7 @@ namespace std
     }
     return os;
   }
-} // end namespace std
+}
 #endif // HAVE_MPI
 
 #endif

dune/common/sllist.hh

@@ -533,15 +533,11 @@ namespace Dune
     /** @brief Iterator positioned at the current position. */
     SLListIterator<T,A> iterator_;
   };
-} // namespace Dune
-
-namespace std
-{
 
   template<typename T, typename A>
-  ostream& operator<<(ostream& os, const Dune::SLList<T,A> sllist)
+  std::ostream& operator<<(std::ostream& os, const SLList<T,A>& sllist)
   {
-    typedef typename Dune::SLList<T,A>::const_iterator Iterator;
+    typedef typename SLList<T,A>::const_iterator Iterator;
     Iterator end = sllist.end();
     Iterator current= sllist.begin();
 
@@ -557,10 +553,6 @@ namespace std
     os<<"} ";
     return os;
   }
-} //namespace std
-
-namespace Dune
-{
 
   template<typename T, class A>
   SLList<T,A>::Element::Element(const MemberType& item, Element* next)