ft-lambda: consider using transient sub-bindings and/or fix hashCode/equals

[lalmeras]

Using transient sub-binding may be an interesting trick for Serializable behavior. It should not trigger any regression, and enhance serialization performance.

Maybe allowing to use a Binding registry (at least for rootless bindings) can be interesting.

We should at least a better equals/hashCode implementation (as for the moment two bindings for the same class are not instance-equal after a deserialization).