Lone hit area only includes samples above threshold

Created by: JelleAalbers

In strax, the left and right boundaries of a hit are set by the region that actually crossed the threshold. To ensure we include the full area in integrations, we extend the boundary of peaks outwards by some amount.

For lone hits, we do not do this, but instead report the hit area directly. Thus, unless the pulse compression filter is activated, the lone hit areas will be biased downwards very significantly compared to actual 1 PE areas. With the pulse compression filter active, the lone hit area is instead biased slightly upwards, since the filter can cause 1PE pulses to become slightly negative around their maxima.

We could accept this, change the hit definition, or compute lone hit integrals with the left/right extension. The latter should probably be a separate function rather than changing the hitfinder, unless we want to apply the extensions without regard to neighboring peaks/hits or record breaks.