Sadly, this involves a small API change, but I don't believe anyone was
using the argument I had to remove (because we were sometimes passing a
wrong value, and there is not way to compute the right value at that
point in the code.)
Also sadly, the code to compute the context we are importing into is now
rather spaghetti-like, but it works.
* Support for old non-standard cron for quiz reports dropped. (Standard
cron support was added in 2.2
* Cron support added for qbehaviour, qformat and quizacces plugins.
* qtypes were already supported in the standard way.