Creates a ComboBox cell factory for use in ListView controls. By default, the ComboBoxCell is rendered as a Label when not being edited, and as a ComboBox when in editing mode. The ComboBox will, by default, stretch to fill the entire list cell.

Parameters:

<T>     The type of the elements contained within the ListView.

converter     A StringConverter to convert the given item (of type T) to a String for displaying to the user.

items     Zero or more items that will be shown to the user when the ComboBox menu is showing. These items must be of the same type as the ListView items list, such that upon selection, they replace the existing value in the items list.

Returns: A Callback that will return a ListCell that is able to work on the type of element contained within the ListView.

`<T>`		The type of the elements contained within the ListView.
`converter`		A `StringConverter` to convert the given item (of type T) to a String for displaying to the user.
`items`		Zero or more items that will be shown to the user when the `ComboBox` menu is showing. These items must be of the same type as the ListView items list, such that upon selection, they replace the existing value in the `items` list.