Making sample ID field in genotype nullable.
Making sample ID field in genotype nullable.

kcompher/adam,SwathiMystery/adam,bigdatagenomics/adam,kcompher/adam,tomwhite/adam,tdanford/adam,VinACE/adam,tomwhite/adam,SwathiMystery/adam,FusionWorks/adam,FusionWorks/adam,erictu/adam,rnpandya/adam,allenday/adam,rnpandya/adam,VinACE/adam,allenday/adam,tdanford/adam,heuermh/adam,massie/adam,rnpandya/adam,massie/adam,tdanford/adam,erictu/adam,heuermh/adam,FusionWorks/adam,bigdatagenomics/adam,erictu/adam,laserson/adam,gazimahmud/adam,laserson/adam,massie/adam,laserson/adam,VinACE/adam,tdanford/adam,gazimahmud/adam,heuermh/adam,SwathiMystery/adam,erictu/adam,allenday/adam,heuermh/adam,tomwhite/adam,bigdatagenomics/adam,kcompher/adam,bigdatagenomics/adam,SwathiMystery/adam,kcompher/adam,gazimahmud/adam,allenday/adam,gazimahmud/adam,laserson/adam,FusionWorks/adam,VinACE/adam,massie/adam,tomwhite/adam,rnpandya/adam