Allow setting environment for TestingNodeModule
Remove unused class DiscoveryFutures
Retry quickly when discovery failure occurs
Guarantee services are refreshed in returned future
Assure ResponseHandler is called once and only once

Change executeAsync to return a ListenableFuture instead of a CheckedFuture since checked future requires multiple calls to response handler
Remove use of CheckedFuture from most APIs
Add constructor with environment and pool to TestingNodeModule
add TestingJmxModule
 Handle case where responsehandler throws an undeclared throwable (e.g, subclass of error)
Add entire json response text to exception message