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 
Adding info:

 In:
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4190
Stephan T. Lavavej argues:

> (In the future, I'll argue that bind() itself has been superseded by lambdas
> and especially generic lambdas, so bind() should be deprecated, but that
> isn't part of this proposal.)

I do not think we should wholesale replace bind with lambdas.  However the writing is on the wall that lambdas will probably replace bind.  In cases where both bind and lambda work equally well (including taking current compiler support into consideration), we should probably go with lambdas.