Use interpolated crosspoint for trigger

[TickTock-]

I noticed that the oscilloscope waveform centers on the first sample above (or below if neg edge selected) the set trigger level. This results in a lot of jitter on the output. This can be cleaned up a lot with a linear interpolation between the two samples straddling the trigger level.
Ex. given two sample points P1=(t1,v1)=(-40ns, -1.5V) and P2=(t2,v2)=(120ns, +0.5V), and trigger set to rising edge and offset (os) to 0V the software currently centers everything on the second sample shifting all points by 120ns. To avoid the jitter, instead all points should be shifted by t1+(t2-t1)*(os-v1)/(v2-v1)=-40+(120--40)/(0--1.5)/(0.5--1.5)=80ns