change regex to match chrom names with _ or lowercase characters in
change regex to match chrom names with _ or lowercase characters in

willmclaren/ensembl-rest,ens-lgil/ensembl-rest,ens-lgil/ensembl-rest,willmclaren/ensembl-rest,helensch/ensembl-rest,helensch/ensembl-rest,willmclaren/ensembl-rest,ens-lgil/ensembl-rest,helensch/ensembl-rest,willmclaren/ensembl-rest,ens-lgil/ensembl-rest,ens-lgil/ensembl-rest,helensch/ensembl-rest,willmclaren/ensembl-rest,helensch/ensembl-rest