Implement security patch and cpulimit

CPULimit: GSD now supports managing CPU time. Please make sure you
install cpulimit by following the node setup documentation.

Security patch details: Prior to this release GSD would allow an
attacker to run arbitrary commands through a maliciously crafted plugin
on the server, or a malicious jar file in place of the server jar. This
update addresses those issues by running the process as a user with
/bin/false as a shell, as well as setting the correct file permissions
on all files.

Misc Fixes: Less verbose logging in places, better logging in others.