Fix touch with Weston

Work around the missing touch_frame after the last touch_up.

Task-number: QTBUG-36602
Change-Id: Iccb03bdc8b430c7cefc097c3c84e50be676c7fe7
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Wayland: correct touch location

The window margins were offsetting the touch point in the wrong
direction.

Task-number: QTBUG-36602
Change-Id: Id8b31d2de4051f36d3ff4e088bbc9bd7cc84ca13
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Wayland: can drag a window by its titlebar using the touchscreen

It was already possible to drag it via the mouse but not via touch.

Task-number: QTBUG-41085
Change-Id: Ia52c7124fb2f1aa0331897bd072fcf09fb78aa1a
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>