Fix wlgen Ramp

Make sure we get the expected number of steps, even if the delta_pct is not an exact divider of (end_pct-start_pct) but is slightly too large instead. If the delta_pct is not an exact divider of (end_pct-start_pct), we'll end up with a final phase that has a duty cycle that does not match end_pct. Force the last phase to have a duty cycle of end_pct.

Also add a debugging aid.