Correct TIME 0 values for non-standard IOPs

Add a MODELRATE_CPS ( CPS ) variable to the model build.  Use this to calculate
dynamic limits for TIME0.

Change TIME0 measurement to always run on second cycle no matter the rate, and to
take rate into consideration for the calculation.

Fixes both fast (524K) and slow (33K) IOP models, specifically aimed at making LLO pemmid look good.