find Negative Peaks
fun findNegativePeaks(positive: NucSeq, rangeList: List<SRange>, pairingFunc: (NucSeq, NucSeq) -> Boolean, count: Int): Set<SRange>
Find peaks with criteria matching that specified by the user-supplied pairing function. This method assumes the sequence in the NucSeqRecord hasn't changed from the original, and the ranges indicate which subsection of the sequence to pull.