Only the latest log was kept as node.log.old. Now, log files are numbered (node.log.1, node.log.2 and so on). Also node.log is now a hard link to the current log file. rad node stop will delete node.log (note that node.log.x stays intact) and rad node start will delete node.log before it creates node.log.y in case the node crashed.

Also, when running in foreground mode, now a log file is created. It just contains the hint that the node was started in foreground mode, just to avoid confusion.

REVIEW: using a more business logic approach

Flexing the sans-io muscles to capture the business logic around rotating the log into a struct LogRotator.

The IO implementation is then captures in the LogRotatorFileSystem.