add mart_genotypes opt, improve forking, add FASTA file support for faster transcript_variation
add mart_genotypes opt, improve forking, add FASTA file support for faster transcript_variation

Ensembl/ensembl-variation,willmclaren/ensembl-variation,dbolser/ensembl-variation,Ensembl/ensembl-variation,willmclaren/ensembl-variation,willmclaren/ensembl-variation,dbolser-ebi/ensembl-variation,Ensembl/ensembl-variation,dbolser/ensembl-variation,Ensembl/ensembl-variation,dbolser/ensembl-variation,willmclaren/ensembl-variation,dbolser-ebi/ensembl-variation,willmclaren/ensembl-variation,Ensembl/ensembl-variation,dbolser/ensembl-variation,dbolser-ebi/ensembl-variation