code: function nextTile()
      {
          clog('nextTile');
          rect.emit('tile', tile);
          tile = {};
          if (rect.tilex < rect.widthTiles)
          {
              rect.tilex++;
              //clog([rect.tilex, rect.tiley]);
              return cli.readHextileTile(rect, cb);
          } else {
              clog('===================== new row! ' + rect.tiley);
              rect.tilex = 0;
              if (rect.tiley < rect.heightTiles)
              {
                  rect.tiley++;
                  //clog([rect.tilex, rect.tiley]);
                  return cli.readHextileTile(rect, cb);
              } else {
                  clog('====================')
                  clog(rect);
                  return cb();
              }
          }   
      }
docs: calculate next tilex & tiley and move up 'stack' if we at the last tile