Parallelize the QtWayland build.

Remove CONFIG += ordered and specify explicit dependencies to allow the
Compositor and Client modules to be built in parallel.

Change-Id: Ifc7ccbdb6fe6623609ad050ede1cbc995499e524
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
QWaylandDecoration: Remove some unused members

Change-Id: Ia98190adbd3f710de6734c10062792ce3f4547d9
Reviewed-by: Giulio Camuffo <giulio.camuffo@jollamobile.com>
Fix window decorations being leaked.

Change-Id: If0483f5e81a033b275ddc14eb1e44ff82fa1ce65
Reviewed-by: Giulio Camuffo <giulio.camuffo@jollamobile.com>