add customize x y for genelabelrotation 0; add --outputprefix for customized output

[Tong-Chen]

1. Sorry for not syncing all codes about genelabelrotation.
2. This commit is mainly about --outputprefix.

[tanghaibao]

@Tong-Chen

Thanks for the contribution. I've resolved the conflicts and merged in (I also made some small mistakes when I did it but those were reverted).

To prevent future conflicts, please make sure that you sync the fork and set my repo as the upstream according to:
https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork