changes for new ArrayExpress xref source
changes for new ArrayExpress xref source

mjg17/ensembl,james-monkeyshines/ensembl,at7/ensembl,danstaines/ensembl,at7/ensembl,muffato/ensembl,muffato/ensembl,Ensembl/ensembl,muffato/ensembl,mjg17/ensembl,danstaines/ensembl,james-monkeyshines/ensembl,Ensembl/ensembl,mjg17/ensembl,james-monkeyshines/ensembl,danstaines/ensembl,Ensembl/ensembl,willmclaren/ensembl,willmclaren/ensembl,mjg17/ensembl,Ensembl/ensembl,at7/ensembl,james-monkeyshines/ensembl,muffato/ensembl,at7/ensembl