removed dependency on PyVCF since it was failing to parse some VCF files
removed dependency on PyVCF since it was failing to parse some VCF files

macarthur-lab/xbrowse,macarthur-lab/xbrowse,ssadedin/seqr,macarthur-lab/xbrowse,macarthur-lab/xbrowse,ssadedin/seqr,macarthur-lab/xbrowse,macarthur-lab/seqr,macarthur-lab/xbrowse,macarthur-lab/seqr,ssadedin/seqr,macarthur-lab/seqr,macarthur-lab/seqr,ssadedin/seqr,macarthur-lab/seqr,ssadedin/seqr