title: Reversing or reverse iterating an unordered_map
body: <p>I'm trying to print the contents of an unordered_map in reverse order, but 
  it doesn't have rbegin or rend, so you can't use reverse_iterator. How is reversing of the unordered_map supposed to be done?</p>
  
  <p><strong>EDIT (from comment):</strong> I want the keys to be in the order they were inserted in, hence I cant use map. The keys appear to stay in the insertion order, but I need them reversed.</p>