GDSTP screen "IO" time modified to show most of ADC read time in microseconds.

"TOTAL" time now reads this same IO time plus the time to run through all 'UNDERSAMPLE' or 'clock_div' model calculations.

For most models that amounts to only one calculation, but for a fast ADC model running at 524 Hz, but spitting out data at 65 Hz, that's all 8 calculations.

Closes #280 (closed)

assigned to @jonathan-hanks

changed the description

merged

mentioned in commit e9b2883b