Added the public function "editActiveCell" to make it possible to trigger editing the active cell from the outside i.e. if an external contextmenu is used to trigger editing entries this is needed
the editor parameter is optional. If its not provided the editor is taken from the options. I just mimicked the behaviour of the underlying method so that it is generally possible to pass an editor.
Added the public function "editActiveCell" to make it possible to trigger editing the active cell from the outside i.e. if an external contextmenu is used to trigger editing entries this is needed