* avoid implict casts

merge to release

[[Imported from SVN: r5877]]

dune/common/fvector.hh

@@ -108,7 +108,7 @@ namespace Dune {
     {
       static inline typename FieldTraits<K>::real_type sqrt (const K& k)
       {
-        return std::sqrt((double)k);
+        return typename FieldTraits<K>::real_type(std::sqrt(double(k)));
       }
     };