--cleanup to remove local files if no remote is given

[Ole Tange]

At my last presentation it was suggested to have an option that would
treat the input as files and remove these after running the job.

--cleanup already does this for remote jobs.

Would it make sense that if you do not have remote jobs that --cleanup
will remove the input?

# This would remove the files
ls | parallel --cleanup echo

# This would only remove the files on server2
ls | parallel --cleanup --transfer -S :,server2 echo

# What should this do?
ls | parallel --cleanup -S : echo

I am a bit worried that --cleanup might do something the user would
not expect and removing files is the kind of 'unexpected' that is
dangerous.

/Ole