kfunc: Moved the kt_fisher_exact test from the original bcftools into htslib
bgzf: Fixed typo in block_address calculation in bgzf_seek
synced_vcf_reader: new bcf_sr_get_line macro and fix in vcf/bcf index interator initialization
vcf: Minor bug fixes and API touches
kseq,hts: Enable seek() on kstreams and hts_useek(),hts_utell() on htsFiles. New module which allows sweeping BCF/VCF files both fwds and bwds