An explain output feature

[Martin Owens]

An explain() function which prints out a human readable understanding of
what the crontab is saying:

0 */2 * * * would be:

"Every two hours"

10 */2 * * 1 would be:

"Every Monday, every two hours, at ten past the hour"

This might be worth turning into a separate module or tying into an existing module if available.

[Martin Owens (doctormo)]

This is now fixed using the optional extra module cron-descriptor. It's not perfect, but the errors are upstream. :-D