This new messaging system replaces all the various email_to_user() calls.
They are now replaced by events triggers, and the messages are then
processed centrally according to user preferences and sent to one or more
processors (email, popup, jabber etc...)
This code is not finished yet, a lot of work still has to be done on the
interface. However, the basic structure is there and should be working.
Luis and I will be reviewing and polishing this heavily in the next few weeks.
It's not at all well-tested yet (I made a lot of changes to it just tonight)
but it's late and I am literally sick (with flu) and tired so I'm checking
this in and going to bed.
Please fix all the bugs for me. ;-)
The internal method (the default) simply replicates Moodle's
existing behaviour and is working fine.
The new flatfile module also works.
There is no admin config interface yet, I'm still implementing
this using templates.
