Non-zero exit status

[jayvdb]

If there were any modifications, it would be helpful if there was a non-zero status.

This would allow moban to be used in CI to detect (and usually fail) if all files were not in sync.

This could be done like git diff --exit-code which adds the exit code to reflect there were changes.

[chfw]

what about returning the number of templated files? 0 for no files, 1 for 1 files... n for N files.

[chfw]

1 for having and acted on changes, 2 for errors.

Just checked that N is impossible as the upper limit is 255.

[chfw]

please be notified that I have renamed setupmobans to pypi-mobans.