Fix a crash in QQuickItem::nextItemInFocusChain()

There is no window object yet when Component.onCompleted.

Task-number: QTBUG-33298
Change-Id: I0608d52ee9fe52a0e2c18e81ad7ba99b56078be4
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>
Docs: fix QtQuick2::Item::layer.sourceRect type

Change-Id: Ia02f451b07638ec2e3f0355b89bf9f7356da44a6
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Merge remote-tracking branch 'origin/stable' into dev

Change-Id: I899f3b517523e4037de50802c0912f7dd960133e
Merge "Merge remote-tracking branch 'origin/stable' into dev" into refs/staging/dev