Support setting owner and timestamps of a symbolic link; support using realtime timer (nano-second resolution) on newer Unix systems.
Add new methods to class Unix:
  getSystemTime()
  setUseUnixRealtimeTimer()
  isUseUnixrealtimeTimer()
  setLinkOwner()
  setLinkTimestamps()
  setFileTimestamps()
  setOwner(String, Password)