Revert "Revert "[C++11] Follow the C++11 specification of operator new.""

This reverts commit 4441ec26.
The minimal required is finally GCC 4.7 or newer (it is actuall 4.9).
Original commit message for d26e5ed3 was
    [C++11] Follow the C++11 specification of operator new.

    The signature changed in C++11 which we require now.
    To get more details see the mailinglost in October 2012.

dune/common/debugallocator.hh

@@ -295,7 +295,7 @@ namespace Dune
 }
 
 #ifdef DEBUG_NEW_DELETE
-void * operator new(size_t size) throw(std::bad_alloc)
+void * operator new(size_t size)
 {
   // try to allocate size bytes
   void *p = Dune::DebugMemory::alloc_man.allocate<char>(size);