acknowledge presence of type_traits header that is not under tr1.

[[Imported from SVN: r5005]]

common/typetraits.hh

@@ -7,6 +7,8 @@
 
 #ifdef HAVE_TR1_TYPE_TRAITS
 #include <tr1/type_traits>
+#elif defined HAVE_TYPE_TRAITS
+#include <type_traits>
 #endif
 
 namespace Dune
@@ -157,6 +159,8 @@ namespace Dune
 
 #ifdef HAVE_TR1_TYPE_TRAITS
   using std::tr1::remove_const;
+#elif defined HAVE_TYPE_TRAITS
+  using std::remove_const;
 #else
 
   /**
@@ -278,6 +282,8 @@ namespace Dune
 
 #ifdef HAVE_TR1_TYPE_TRAITS
   using std::tr1::is_same;
+#elif defined HAVE_TYPE_TRAITS
+  using std::is_same;
 #else
   /**
    * @brief Compile time test for testing whether