MergingDigestCompress Method

Re-examines a t-digest to determine whether some centroids are redundant.If your data are perversely ordered, this may be a good idea.Even if not, this may save 20% or so in space. The cost is roughly the same as adding as many data points as there are centroids.This is typically < 10 * compression, but could be as high as 100 * compression. This is a destructive operation that is not thread-safe.

public void Compress()