handlePostBind

Called on the generated model immediately after the main model onBind method has been called.This let's the generated model handle binding of its own and dispatch calls to its onBindlistener.

We don't want to rely on the main onBind method to dispatch the onBind listener call becausethere are two onBind methods (one for payloads and one for no payloads), and one can call intothe other. We don't want to dispatch two onBind listener calls in that case.