Update cron library to dennisfrancis/22a7b1f9c7ae302341d4ef970d4d74583d3de0bc

https://github.com/dennisfrancis/cron/commit/22a7b1f9c7ae302341d4ef970d4d74583d3de0bc
[picnic/rd] Update cronHelp
[rucksack] add Delete() func
[brotzeit] Add remove schedule feature