add ref and alt lengths to vcflength
add ref and alt lengths to vcflength

These are helpful in some contexts, when it would be nice to know
the length of a haplotype call for instance, rather than the
absolute delta of the ref/alt pair.

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