Crontask system! Message Scheduler!

So the Cron Run.php script iterates over a set of registered tasks
and runs each one if the task's shouldRun() function returns true.

The MessageTask has the startings for message sending scheduling.
It can process natural language date strings and convert those
into date/timestamps that can then be used to determine if a message
is due to be sent right now.

The idea is that the server's Crontab will run the Run.php script,
and the MessageTask will iterate over all scheduled messages and
determine which need to be sent out at this run of the task. I would
imagine imposing a 15-minute granularity on times would be acceptable.