TickDuration deprecation

[Walter Bright]

On 11/18/2017 8:17 AM, Jonathan M Davis wrote:
> Folks have asked for the ability to create Durations from floating point
> values too, and I rejected that for the same reason - using floating point
> values with time is just begging for bugs, and Walter backed me up on that
> one.

Yup. It's the same reason one does not do accounting with floating point.

Computer clocks have discrete ticks, they are not continuous. The behavior maps 
cleanly onto integral math, not fuzzy fp math.