- All timers are now handled by a single global timer manager, which simplifies how they handled by the IOSource manager.
- This change flows down a number of changes to other parts of the code. The timer manager tag field is removed, which means that matching connections to a timer manager is also removed. This removes the ability to tag a connection as internal or external, since that's how the connections where differentiated. This in turn removes the `current_conns_extern` field from the `ConnStats` record type in the script layer.