new subroutine to handle new source of allele string data
new subroutine to handle new source of allele string data

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