Rename all QWindow properties that have "window" in them

Rename all QWindow properties that have "window" in them

windowTitle, windowModality, windowIcon and so on are named that way
to be similar to the ones in QWidget.  However QQuickWindow inherits
all of the declared properties, and we would like to have shorter
property names in QML.  If you are working with a Window then it's
obvious the title property is the window title.  Unfortunately,
there must be patches in many other modules which depend on this one.
In order to avoid the need to merge them all at the same time,
there is also patch https://codereview.qt-project.org/#change,39001
which temporarily adds backwards-compatible accessors, which can be
removed after the other modules are able to build without them.

We should not rename windowState to state, because in QML, state
usually drives the state machine for animation transitions etc.
(although QWindow is not an Item, a user might get confused about it).

Related patches are
https://codereview.qt-project.org/#change,39001
https://codereview.qt-project.org/#change,37764
https://codereview.qt-project.org/#change,37765
https://codereview.qt-project.org/#change,37766
https://codereview.qt-project.org/#change,37762

Change-Id: Ie4424ec15fbdef6b29b137f90a2ae33f173edd21
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>