Doc: Small fix for SplitView

SplitView items must set width/height and not
Layout.preferredWidth/Layout.preferredHeight.

Change-Id: Ice888d51c63cbdaf6e0e235c0c7569c4a8794b7d
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>
Adapt to Qt.platform.os rename ("mac" -> "osx")

Change-Id: I089a01bee10b92f85dcdd338c695a3b796b0ecd1
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Merge remote-tracking branch 'origin/release' into stable

Change-Id: I1684510ce4f1b52e3569d8c04e272b1c8fd63c1a
Include qquickstyleitem_p.h only if QT_NO_WIDGETS not defined

Change-Id: I7c2045acbd2331ec4ab7b14cf7694332f0b6a49b
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>