code: function ( eventName, handler ) {
          var events = this.events[ eventName ],
              handlers = [],
              i;
          if ( !events ) {
              return;
          }
          if ( $.isArray( events ) ) {
              for ( i = 0; i < events.length; i++ ) {
                  if ( events[i].handler !== handler ) {
                      handlers.push( events[ i ] );
                  }
              }
              this.events[ eventName ] = handlers;
          }
      }
docs: Remove a specific event handler for a given event.
  @function
  @param {String} eventName - Name of event for which the handler is to be removed.
  @param {OpenSeadragon.EventHandler} handler - Function to be removed.