vcffirstheader now works with empty vcf files
vcffirstheader now works with empty vcf files

vcflib/vcflib,glennhickey/vcflib,tomdcsmith/vcflib,harshinamdar/vcflib,wzugang/vcflib,ashishjain1988/vcflib,ashishjain1988/vcflib,ekg/vcflib,glennhickey/vcflib,zhmz90/vcflib,harshinamdar/vcflib,glennhickey/vcflib,wzugang/vcflib,harshinamdar/vcflib,tomdcsmith/vcflib,ekg/vcflib,travc/vcflib,glennhickey/vcflib,ashishjain1988/vcflib,zhmz90/vcflib,glennhickey/vcflib,vcflib/vcflib,harshinamdar/vcflib,vcflib/vcflib,harshinamdar/vcflib,wzugang/vcflib,travc/vcflib,wzugang/vcflib,glennhickey/vcflib,vcflib/vcflib,zhmz90/vcflib,harshinamdar/vcflib,vcflib/vcflib,vcflib/vcflib,vcflib/vcflib,ekg/vcflib,ashishjain1988/vcflib,travc/vcflib,zhmz90/vcflib,ekg/vcflib,wzugang/vcflib,tomdcsmith/vcflib,ashishjain1988/vcflib,ashishjain1988/vcflib,zhmz90/vcflib,zhmz90/vcflib,vcflib/vcflib,wzugang/vcflib,ekg/vcflib