londiste compare: calculate checksum
londiste compare: calculate checksum

Also allow specify format string.

Patch by Hannu Krosing

overdrive3000/skytools,overdrive3000/skytools,markokr/skytools,markokr/skytools,tarvip/skytools,tarvip/skytools,markokr/skytools,overdrive3000/skytools,tarvip/skytools