code: function toStringRegularHoliday(value) {
    if (typeof value === 'function') {
      return value;
    }
    var weeks = Object.keys(value.week).map(x => CONFIG.JWEEK[x]);
    var days = Object.keys(value.day);
    var xweeks = Object.keys(value.xweek).map(x => {
      var sp = x.split('-');
      return sp[0] + CONFIG.JWEEK[sp[1]];
    });
    return [].concat(weeks).concat(days).concat(xweeks).join(', ') || null;
  }
docs: 定休日をビルドする
  {
  week : {'0': true, '6': true},
  day  : {'20': true, '30': true},
  xweek: {'2-2': true, '3-2': true}
  } ->
  '日, 土, 20, 30, 2火, 3火'
  
  @param  {Object} value
  @return {String}