First step towards porting sequence wrappers to V4

The idea is to wrap sequence container types such as QStringList or
QList<int> in a JS object that behaves like an array and also shares the
prototype.

The next step is to generalize the QStringList implementation to be re-usable
for the other sequence types.

This also required extending the object iterator with support for these
kind-of array types.

Change-Id: I5f0a14f904233944297708037c944964f1b74923
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Another fix for getting more of the QML based tests running

The QML testlib uses the in operator on the QObject bindings, which provides
properties using the named fallback property query/enumerator. We need to
include those in Object::__hasProperty__, which is used to implement "if (foo in bar")

Change-Id: Ib30a9e9d90e0e2379e655f5282c269f1b5cceb8d
Reviewed-by: Lars Knoll <lars.knoll@digia.com>