major fixes to vcfintersect, unioning and intersecting
major fixes to vcfintersect, unioning and intersecting

Affects VCF-VCF comparison code, many small bugfixes.

ashishjain1988/vcflib,alimanfoo/vcflib,tomdcsmith/vcflib,ekg/vcflib,travc/vcflib,vcflib/vcflib,jewmanchue/vcflib,jewmanchue/vcflib,ashishjain1988/vcflib,hyphaltip/vcflib,vcflib/vcflib,jewmanchue/vcflib,harshinamdar/vcflib,glennhickey/vcflib,alimanfoo/vcflib,andersje/vcflib,wzugang/vcflib,hyphaltip/vcflib,andersje/vcflib,zeeev/vcflib,alimanfoo/vcflib,vcflib/vcflib,jewmanchue/vcflib,alimanfoo/vcflib,ashishjain1988/vcflib,zeeev/vcflib,ashishjain1988/vcflib,wzugang/vcflib,harshinamdar/vcflib,zeeev/vcflib,tomdcsmith/vcflib,wzugang/vcflib,travc/vcflib,zhmz90/vcflib,andersje/vcflib,jewmanchue/vcflib,alimanfoo/vcflib,jewmanchue/vcflib,ashishjain1988/vcflib,andersje/vcflib,ekg/vcflib,hyphaltip/vcflib,vcflib/vcflib,wzugang/vcflib,harshinamdar/vcflib,glennhickey/vcflib,tomdcsmith/vcflib,vcflib/vcflib,zeeev/vcflib,glennhickey/vcflib,harshinamdar/vcflib,hyphaltip/vcflib,zhmz90/vcflib,andersje/vcflib,wzugang/vcflib,vcflib/vcflib,andersje/vcflib,zeeev/vcflib,zhmz90/vcflib,harshinamdar/vcflib,glennhickey/vcflib,travc/vcflib,zhmz90/vcflib,hyphaltip/vcflib,harshinamdar/vcflib,wzugang/vcflib,ekg/vcflib,glennhickey/vcflib,ekg/vcflib,vcflib/vcflib,glennhickey/vcflib,vcflib/vcflib,zhmz90/vcflib,ekg/vcflib,zeeev/vcflib,hyphaltip/vcflib,zhmz90/vcflib,ashishjain1988/vcflib,alimanfoo/vcflib