add gff children + reformat attribs
add gff children + reformat attribs

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