Allow for -hash backups on a regular schedule

[freaksdotcom]

It would be nice if a backup with the -hash option could be scheduled to run on a less frequent basis, such as weekly or monthly. This would help to catch any changes where the contents may have changed but the length and mtime have not.

[TheBestPessimist]

not sure how this could be scheduled with the current architecture.
I have never used -hash so far though.

Offtopic: i strongly believe that if an app does not change the Modified Time of a file, that app is miss-behaving and I would either try to fix it, or stop using it.