Calling HALSIM_PauseTiming pauses the FPGA clock and notifiers.
Calling HALSIM_ResumeTiming resumes the FPGA clock and notifiers.
Calling HALSIM_StepTiming steps the FPGA clock and runs applicable notifiers.
This will effectively pause TimedRobot and any other notifier-based events,
but of course will not pause user threads that do not use the notifier (e.g.
image processing).
