function GeneralSource() {
    this.actions = new Map();
  }
Create a scroll event for the current default wheel source

@param {Number} x - mouse cursor x coordinate
@param {Number} y - mouse cursor y coordinate
@param {Number} deltaX - scroll delta value along the x-axis in pixels
@param {Number} deltaY - scroll delta value along the y-axis in pixels
@param {String|Element} origin - Origin of the coordinate system.
                                 Either "viewport" or an Element
@param {Number?} duration - Time in ms for the scroll
@param {String?} sourceName - Named wheel source to use or null for the
                              default wheel source
@returns {Actions}