ReliableProxy with reconnection.
Changes for Nov. 25th feedback.
- Don't use Option in constructor.  When maxReconnects = 0 it means no limit.
- Don't assign new serial numbers on when resending.  Instead change Receiver to take a initialSerial parameter.
- Use templates with {} for logging
- Update tunnel var in createTunnel()
- Remove NoRetry message
- Fix some comments
Add ActorPath variation to constructor.  If ActorPath used, go into Reconnect state immediately.