partial revert of preceding: rejected by GCC

this was an half hearted attempt to satisfy CLang,
but GCC as keen as a razor insists on these inherited
functions not being accessible --

seems like the time is over, when GCC used to be forgiving
and CLang briliantly precise...

So the conclusion of this "round trip" is: whenever GCC
also starts whining about shadowed overloaded virtual functions,
we'll just switch to "-Wno-overloaded-virtual" and be done with
that pointless discussion.

Since C++11, we have the Java style override specifier,
which does a way better job at spotting signature mismatches

src/lib/meta/virtual-copy-support.hpp

@@ -200,9 +200,6 @@ namespace meta{
           D& src = static_cast<D&> (*this);
           new(targetStorage) D(move(src));
         }
-      
-      using I::copyInto;
-      using I::moveInto;
     };
   
   
@@ -216,9 +213,6 @@ namespace meta{
           D const& src = static_cast<D const&> (*this);
           new(targetStorage) D(src);
         }
-      
-      using I::copyInto;
-      using I::moveInto;
     };
   
   
@@ -241,9 +235,6 @@ namespace meta{
           D& s = static_cast<D&> (*this);
           t = move(s);
         }
-      
-      using I::copyInto;
-      using I::moveInto;
     };