changed some indexes and the structure of pairwise_ld table
changed some indexes and the structure of pairwise_ld table

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