BUG-12200: exists has --live flag to say live only
BUG-12200: if live and cluster not found in the list of finished apps, return false (case that missed testing)
Add sign correction to shell so a return code of 255 is remapped to -1
hoya-core tests of exists outcomes
Merge branch 'feature/BUG-12200' into develop
BUG-12200: update release notes, specification and man page