Refactor Boot/Quit and related methods

I'm marking this as WIP because I want us to spend as much time as possible testing this. It might also need more UnitTests.

This MR refactors SATIE's boot/quit mechanisms. Some notable changes:

• Satie has a new attribute called status which tells us what state Satie is in: \initialized, \booting, \running, \quitting
• waitForBoot now does various things based on the current status
• It's no longer problematic if you call Satie.boot then Satie.waitForBoot
• Improved Satie init
• UnitTests now check \running status