Tootfinder

Starting to look at some performance improvements for various scopehal filters as I begin the push for v0.2.
The benchmark dataset is P/N legs of 100baseTX Ethernet sampled at 500 Msps with a ThunderScope.
At 50M point memory depth, each waveform is 100 MB in size (2 channels * 8 bits * 500 Msps) and covers 100ms of real time.
The filter graph currently takes just shy of a second to run, meaning we're at 10% of real time. I want to improve on this.