Before we had the option of eager evaluation, we were able to use the
dirty flag to detect whether we are recursing. However, eager properties
will lead to a evaluateIfDirtyAndReturnTrueIfValueChanged call, and that
in turn will clear the dirty flag.
Introduce a new member to detect that situation, and set the bindings
error state to BindingLoop if we detect that kind of loop.
Change-Id: If40b93221848bd9e9422502318d992fad95b0b74
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
1e883cf9b5