Initial (broken) support for running plans
Working run support!

Doesn't handle scheduled execution (cron-style) yet, no notifications,
but it totally runs plans from the HTTP trigger and updates the status
on the run appropriately as it executes.
More flexibility for triggers and notifications

Triggers are now an array, so you can have multiple cron-style
triggers in a single plan, or possibly other triggers I have yet
to even imagine), as are notifications, so you can have different
notifications go out based on different run finish conditions).