Size added

[[Imported from SVN: r2790]]

fem/common/discretefunction.hh

 // -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 // vi: set et ts=4 sw=2 sts=2:
-
 #ifndef DUNE_DISCRETEFUNCTION_HH
 #define DUNE_DISCRETEFUNCTION_HH
 
@@ -90,6 +89,11 @@ namespace Dune {
       return asImp().name();
     }
 
+    //! The size of the discrete function
+    int size() const {
+      return asImp().size();
+    }
+
     //! the implementation of an iterator to iterate efficient
     //! over all dofs of a discrete function
     DofIteratorType dbegin ()