Fix Resolver shutdown behaviour

* Add Resolver prefix to logging.
* Fix AsyncObject::removeReference() logic.
* Fix work remaining logic.

I spotted this while playing around with Application Stoppable behaviour. 
Reviewers: @nikb @vinniefalco 
"They don't have a name, you cant search for them, and you can't attach javadoc comments to them."

Absolutely, but the same is true of `std::bind`.