Move checkResources() to Kronolith::, and out of the concrete Event_Sql driver.

Move checkResources() to Kronolith::, and out of the concrete Event_Sql driver.

Move code for auto-accepting resources out of the Event driver and put
it into Kronolith:: Call it from Kronolith_Event::save() method (not 100%
sure about leaving it there, or just calling it in client code before saving
where appropriate).