CN - Main loop now using CoOS flag set within Systick ISR to determine if main loop code (IMU etc) should be executed.
Note that Systick frequency is 10kHz, so looptime config value is only good to 100us resolution. I don't think that's the end of the world, esp. given the amount that the loop time fluctuates by (easily +- 200us).
Would like to get all periodic tasks on main loop operatng off flags so that it eventually can yield to a lower priority task that handles low priority work (e.g. LEDs?).