Listen for script exit, and close processes

[ebebbington]

Summary

What:

Using signals, listen for if the user exits the script using CTRL+C or CMD+C, and if so, close the processes

Why:

Say something hangs, the user is going to CTRL+C to close it - this means Sinco won't be able to close the subprocess, leading to zombie processes running on the users computer. If the user does this 3 times for chrome, they can have 15 zombie processes running

How:

Wait for denoland/deno#12512, also add a duration param to all api methods, that is passed to the sendWebsocketMessage method, for example

sendWSMessage(...) {
  ...
  const intervalId = setTinterval(async () => {
    count++
    if (count === duration) await this.done("Took too long")
  })
  await messagePromise