allow first pass and hires pass to use a single prompt to do different prompt...

allow first pass and hires pass to use a single prompt to do different prompt editing, hires is 1.0..2.0:
  relative time range is [1..2]
  absolute time range is [steps+1..steps+hire_steps], e.g. with 30 steps and 20 hires steps, '20' is 2/3rds through first pass, and 40 is halfway through hires pass