PSQ_DAScale (Adapt): Enhance it

- Ignore sweeps with negative fI slopes for the DAScale estimation
- Store a new QC value if the fI slope is finite and negative
- Using this new QC we are now also done if:
  - We have to consecutive negative fI slope values (as usual failing
    sweep QC sweeps can be in between)
  - or we have a passing fI slope and a consecutive (as above) negative fI
    slope value
  If we finish due to these two conditions we also fillin another DAScale
  in between the positive FI slope sweep and the first negative fI slope
  value.
- We now use the new analysis parameter DAScaleNegativeSlopePercent,
  defaulting to 50%, to calculate a new DAScale value after a negative
  slope. We use the percentage of the maximum DAScale step for that.
- Add a new labnotebook entry which denotes if a value is filled in or not
- Also a bug is fixed which did not ignore fillin sweeps when trying to
  determine if the set is passing.
- And similiar bug could result in fillin sweeps being marked as fI slope
  passing.

Author: t-b