Add role type to pid check?

[kwaping]

What do you think about adding role type to pid check? In the current state, you can launch a "hub" type, then set it to status stopped with type "node". This seems unsafe.

If you like the idea, I have a PR ready to go, just have to write some tests and docs. I have tested my code functionally and it works great - can start/stop a hub and node on the same machine independently.

[ddavison]

sounds great @kwaping ! no need to wait on me! send that PR if you still have it handy! :)