Pre-exit cleanup callback

Really enjoying using Vorpal so far! Thank you guys for making such an awesome library happen.

One thing I'm trying to chase down is how to gracefully quit an app I'm working on. I'm emulating a virtual real-world device that does a thing on an interval. When I ctrl-c ctrl-c to exit that device, that interval keeps going and I'm forced to kill node directly as it keeps going forever. I'd like to be able to cancel that and any other async action that may be pending in an exit function.

I couldn't find any events to listen in to for this, and using the API for process itself seems a bit more haphazard than I'd like.

Any plans for this? Elegant workarounds?