code: function hashStyle(_) {
      var hash = '';
      
      if (_['marker-symbol']) hash = hash + 'ms' + _['marker-symbol'];
      if (_['marker-color']) hash = hash + 'mc' + _['marker-color'].replace('#', '');
      if (_['marker-size']) hash = hash + 'ms' + _['marker-size'];
      if (_['stroke']) hash = hash + 's' + _['stroke'].replace('#', '');
      if (_['stroke-width']) hash = hash + 'sw' + _['stroke-width'].toString().replace('.', '');
      if (_['stroke-opacity']) hash = hash + 'mo' + _['stroke-opacity'].toString().replace('.', '');
      if (_['fill']) hash = hash + 'f' + _['fill'].replace('#', '');
      if (_['fill-opacity']) hash = hash + 'fo' + _['fill-opacity'].toString().replace('.', '');
      
      return hash;
  }
docs: ## Style helpers