--regress switch about rdiff-backup

[frankcrawford]

@ericzolf while I can understand adding this is not a top priority for adding into rdiff-backup, it would be worth including @dominicraf rdiff-backup-regress.sh script in the tools directory or somewhere else, or at least adding a note in one documentation about it's existence

What do you think?

[ericzolf]

I think, good idea. Can you take care?

I'd suggest at the same time to move misc to tools/helpers and put the script in there. Make sure it has a small explanation header.