Fix of error when using DataView with Timeline

When I tried to use Timeline with DataView instead of DataSet I got following error:

    Uncaught TypeError: undefined is not a function vis.js:7517
    Timeline.getItemRange vis.js:7517
    Timeline.fit vis.js:7480
    Timeline.setItems vis.js:7413
    Timeline vis.js:7144
    (anonymous function) 01_basic.html:36

Similar errors appeared when I tried to edit items:

    Uncaught TypeError: undefined is not a function vis.js:5606
    (anonymous function) vis.js:5606
    options.onAdd 08_edit_items.html:38
    ItemSet._onAddItem vis.js:5604
    triggerEvent vis.js:22050
    tapGesture vis.js:22964
    detect vis.js:22653
    bindDomOnTouch vis.js:22176

The documentation says that it should work, so I've made it actually work :-)