Include QWindow instead of QWidget for Qt 5
Include QWindow instead of QWidget for Qt 5

RevBy: Jon Nordby, Michael Hasselmann

Full, original commit at 9f1209cc39d177cd35032bcb207391ee30038720 in maliit-framework

perencia/inputcontext-qt4,maliit/inputcontext-qt4,maliit/inputcontext-qt4