NOTE: Downloaded update JARs are now expected to have been XORed with 0x5A!
This is to help prevent Windows Firewall from blocking update downloads
based on deep packet inspection.
Download read timeout reduced from 5s to 3s.
Download locations reordered so github entries are at the top as they have
better CDNs.
ApplyUpdate now assumes null response from GET /admin/stop means node
is not running.
ApplyUpdate now checks replacement JAR actually exists before attempting
to overwrite previous version.
ApplyUpdate now tries to use Windows EXE launcher in preference to raw
java command line. (This should improve Windows installer behaviour
in detecting running process and possibly firewall implications too).
