nestd and host don't die when bash sends kill signal

[miyu]

Regression from previous behavior, pretty sure this has to do with the fact that nestd and host are now windows applications. Just a minor annoyance.

[miyu]

Probably not trivial to fix, especially since init.exe now launches nestd.

A potential workaround would send a shutdown signal to updated hatchlings, have nestd (which we shouldn't be touching too much) update to the development egg, then restart the hatchling.