Add 'contains' methods just like the mappers in dune-grid have them.

[[Imported from SVN: r9955]]

dune/gfe/parallel/globalp1mapper.hh

@@ -76,6 +76,15 @@ namespace Dune {
       return localGlobalMap_.find(localIndex)->second;
     }
 
+    template <class Entity>
+    bool contains(const Entity& entity, uint i, uint codim, Index& result) const
+    {
+      if (codim != GridView::dimension)
+        return false;
+      result = subIndex(entity,i,codim);
+      return true;
+    }
+
     Index localIndex(const int& globalIndex) const {
       return globalLocalMap_.find(globalIndex)->second;
     }

dune/gfe/parallel/globalp2mapper.hh

@@ -108,6 +108,16 @@ namespace Dune {
       return localGlobalMap_.find(localIndex)->second;
     }
 
+    template <class Entity>
+    bool contains(const Entity& entity, uint i, uint codim, Index& result) const
+    {
+      Index localIndex;
+      if (not p2Mapper_.contains(entity, i, codim,localIndex))
+        return false;
+      result = localGlobalMap_.find(localIndex)->second;
+      return true;
+    }
+
     Index localIndex(const int& globalIndex) const {
       return globalLocalMap_.find(globalIndex)->second;
     }