Send snapshot for every x % complete

[bipsendk]

Enhancement request: It would be nice, if a "progress" snapshot could be sent for every x % completed - until 100% complete. That way it would be possible to monitor the job progress via email.
The interval should be user configurable - e.g. for every 2 (2,4,6,8,10...100), 5 (5,10,15,20...100) or 10% (10,20,30,40... 100) complete