ts: Save original recombination position for tree sequence recording #6
Description
meiosis.cpp ["changes" the sampled recombination positions to the nearest position of a marker (and if this is far away possibly also discard double recombination - since that would not be seen with sparse markers)].
We should save the sampled recombination positions for the edge table, while still enabling the "changing" for recombination tracking in SP$recHist since that tracks information in line with the available marker panels.