- Properly handle clock transitions when control flows back and forth
between instruction execution and simh commands.
- Changed Internal Timer from 10 Hz to the MAX(100Hz, HostOSClockHz)
- Changed default idle calibration percent to 50%
- Make sure that error cases (backwards and gap too big) properly advance
the real time while avoiding calibration.
- Fix selection of the calibrated clock.
- Fix logic that sets the idle percentage that controls calibration.