Update documentation for automated signing and Ubuntu 16.04
Update documentation for automated signing and Ubuntu 16.04

dmurphy18/salt-pack,saltstack/salt-pack,dmurphy18/salt-pack,saltstack/salt-pack,saltstack/salt-pack,saltstack/salt-pack,dmurphy18/salt-pack,dmurphy18/salt-pack,dmurphy18/salt-pack,saltstack/salt-pack