Suppress dead letter logging in tests
Remember dead members to allow them refute if they wake up again
Use Stash to queue messages until Http is ready to process them
Implement graceful shutdown using Stop message

Node waits for Http to close before stops itself
Use Config case class instead of an object to allow using different configurations
Use configuration with more aggressive timeouts in tests
Don't needlessly increment incarnation at start
Extract NodeTesting trait
Add tests for refuting suspicion & death
Use compact printer for json responses
Test GET for members