Implement query (aka hasProperty) in QObject bindings

Fixes tst_qqmlecmascript::in() auto-test.

Change-Id: Ic42cc566f6ed8077f7aa7d75c0c92236c34c91b8
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Remove v8 usage in two places

Change-Id: I26343f3aaa89ea956a890955ce84894f96ebd67d
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>