fix(fleetctl): remove os.Exits from fleetctl commands
Merge pull request #483 from jonboulle/journal

fix(fleetctl): remove os.Exits from fleetctl commands
feat(fleetctl): sort machines by machineid in list_machines output
feat(fleetctl): add custom fields option to list_units
Merge pull request #473 from jonboulle/473

feat(fleetctl): list machines in consistent/sorted order
Merge pull request #337 from jonboulle/337

Allow user to define fields returned in fleetctl list-units
feat(fleetctl): add unit SHA field to list-units
Merge pull request #179 from jonboulle/179

list-units should show unit hash
feat(unit): add InstanceUnit helpers
feat(job): substitute Requirements for instance unit jobs