DynamicList - consistent setSize() behaviour

  - expansion of a list beyond the currently addressed list size
    changes both the allocated size and the addressed list size

  - contracting list below the currently addressed list size
    changes the addressed list size only.

  If someone really wishes to increase the underlying allocated list size
  without touching the addressed list size:

      prevSize = myList.size();
      myList.setSize(largerSize);
      myList.setSize(prevSize);

  or introduce an equivalent allocSize(const label) method if this is needed