code: private Tuple<String,String> getOverrideEntry( final String    key )
      {
          for ( String    prefix : _overrides )
          {
              String    override = prefix + "." + key;
              String    value    = getPropertyValue( override );
  
              if ( value != null )
              {
                  return new Tuple<String,String>( override, value );
              }
          }
  
          return null;
      }
docs: Looks for each instance of "key" in all of the overrides, in order.
  Does not look for a non-overridden version.
  
  @param key
  @return the first override found, or null if no overrides existed