Hard update to QtQml 5.3.0

This change is a copy of src/qml, src/3rdparty/masm and selected
other files from the 5.3.0 release tag, placed into the 5.2.1++
qtdeclarative tree.

It is an attempt to address the issues  that exist in the
earlier versions of V4 while keeping the rest of the declarative
library compatible.

Change-Id: Id83ae7456db8447f125d7f5a085bba5b5f661009
[qtdeclarative] cherry-pick of 39540124dd0900e0c99dcda8c0ebdf4f3cea8d5e
(patched to compile with this version of QtQml)

Fix interaction of QQuickItems with the garbage collector

The QObject ownership of QQuickItem objects is not accessible / mutable
in QML, because the parent property maps to the (dynamic) visual parent.

There are use-cases of creating QQuickItem objects without a QObject parent and
to support this, the visual parent needs to mark its visual children in order
to provide intuitive semantics.

[ChangeLog][QtQuick][Import Behavior Changes] A QQuick Item is now strongly
referenced by its visual parent item, so it doesn't require a QObject parent to
stay alive.

Task-number: QTBUG-35913
Change-Id: Ief2d40ac76298a0cf241ca73ff654c4ecfa12748
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Hard update to QtQml 5.3.1

Another copy of src/qml, src/masm into our repo to
address issues with ARM based JIT code and other issues.

Change-Id: I345344042a2feff98fa5d68e93f9d55c58518ac7
Merge pull request #29 from mer-qt/QtQml-5.3

[qtdeclarative] Upgrade libQtQml to 5.3.1