code: function Observable(cfg) {
          var self = this;
          self.currentTarget = null;
          util.mix(self, cfg);
          self.reset();    /**
       * current event type
       * @cfg {String} type
       */
      }
docs: base custom event for registering and un-registering observer for specified event.
  @class KISSY.Event.Observable
  @private
  @param {Object} cfg custom event's attribute
   
  base custom event for registering and un-registering observer for specified event.
  @class KISSY.Event.Observable
  @private
  @param {Object} cfg custom event's attribute