quickdwm example: remove broken & irrelevant taskbar button

Change-Id: I0f6bb8569ac8b4c3fc03be6f4876a6c1fe6905a4
Reviewed-by: Ivan Vizir <define-true-false@yandex.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Unify QML type names

Currently few of the QML types have a Win-prefix while others don't:
- WinDwmFeatures, WinTaskbarButton, WinTaskbarProgress
- JumpList, JumpListItem, JumpListCategory, ThumbnailToolBar,
  ThumbnailToolButton

In QML it is easy to import stuff into namespaces to avoid potential
conflicts, or to do it just for clarity if one prefers:

import QtWinExtras 1.0 as Win

Win.JumpList {
    ...
}

=> Remove the hardcoded Win-prefix that is unnecessary for QML types.

Change-Id: I699498640e5d7c32695193147323b929cf5dae86
Reviewed-by: Ivan Vizir <define-true-false@yandex.com>
Reviewed-by: Laszlo Papp <lpapp@kde.org>
Reviewed-by: Alan Alpert <aalpert@blackberry.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
ThumbnailToolBar: support dynamic button manipulation

Change-Id: I5c424f883134ea2352f7cda6100525bd6b4a00d8
Reviewed-by: Ivan Vizir <define-true-false@yandex.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>