code: function(type, callback, scope){
              var listeners = _cache[type];
              if (!listeners) {
                  return this;
              }
              if(callback){
                  var len = listeners.length,
                      tmp = [];
                  
                  for(var i=0; i<len; i++) {
                      var listener = listeners[i];
                      if(listener.callback == callback && listener.scope == scope) {
                      } else {
                          tmp.push(listener);
                      }
                  }
                  listeners = tmp;
              }else{
                  listeners.length = 0;
              }
              return this;
          }
docs: 退订
  @param  {[type]}   type     [description]
  @param  {Function} callback 假如传入则移出传入的监控事件，否则移出全部
  @return {[type]}            [description]