Keep phasing when annotating genotypes.
Keep phasing when annotating genotypes.

Prior to this change, `vcfannotategenotypes` did not transfer over
genotype phasing, if it was present.

Fixes #143

ekg/vcflib,vcflib/vcflib,vcflib/vcflib,ekg/vcflib,vcflib/vcflib,ekg/vcflib,vcflib/vcflib,vcflib/vcflib,vcflib/vcflib,ekg/vcflib,vcflib/vcflib,ekg/vcflib,vcflib/vcflib