Add uri to exception message for failed discovery requests
Retry quickly when discovery failure occures
Simplify AsyncHttpClient

Callers of AsyncHttpClient.executeAsync() shouldn't need to write unnecessary exception handling code around the call. Instead they should rely on any ResponseHandler exception being delivered through the AsyncHttpResponseFuture
Modify test cases to demonstrate bug
Demonstrate case where Netty client isn't calling the ResponseHandler.
Fix netty http client exception processing
Demonstrate bug in TestingHttpClient
Allow ResponseHandler.handleException() to return an object.

This is particularly useful if the caller has a default object they want to use in case of error.
Create DefaultingJsonResponseHandler
Allow setting environment for TestingNodeModule
Remove unused class
Guarantee services are refreshed in returned future
Add discovery ServiceSelectorManager