In this commit, we modify the set of default signals we attempt to catch in
order to execute a graceful shutdown. Before this commit, we would attempt
to catch/register for `SIGSTOP`. There're two issues with this
1. `SIGSTOP` is meant to be used in combination with `SIGCONCT` to allow a
process to be paused/resumed. Therefore, our action of shutting down once
received was incorrect.
2. `SIGSTOP` doesn't exist on windows, so users aren't able to compile on
this platform without modifying the codebase.