Adding support for VCF files and genotype phasing.

Inclusion of haplotype phasing requires the BitDataSet to process
heterozygous sites and genotypes. Changed the ordering of the genotype
data to comply with ordering in VCF file.
Added support for haplotype phasing
Anticipating support for haplotype phasing

Anticipating support for haplotype phasing using the collector model.

Eventually haplotype phaser will store solutions in diplotypes.
Handling VCF file input

VCF format is a standard created by 1000genomes. Most used format for
defining variants/haplotypes/genotypes etc....

This adds *basic* support for reading VCF files.