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Added IBD painting
Added a Class to calculate pairwise distance between a sample to test
and all individuals in a reference panel to confirm the input is the
genotype you think it is.
ibdpainting.py contains class VcfDistance to import two VCF files, check
they are compatible and keep the sample names, chromosome labels, SNP
positions and genotype information.
VcfDistance.split_into_windows divides chromosomes up into windows of
fixed length and returns a dictionary of new VcfDistance objects.
VcfDistance.pairwise_distance calculates the pairwise distance from the
input individual to all referencs samples.