Improve handling of Cloud Service connect/disconnect.
Direct access to the NVR is not affected
Prevent hang forever when cloud proxy is turned off after cloud is shutdown.
- No longer using failover
- Use heartbeats instead of failover to detect connection down and other problems. (failover is still used on the Cloud)
- Measures to prevent CloudSessionTimerTask from continuing to try and start the Cloud Proxy when the user selected off (This was a race condition which could occur when the user turned off CloudProxy when the Cloud is offline).