Updated to reflect the fact that a CCDS may be linked to more than one transcript. Hence need to add xrefs only once, i.e. check for existence before adding.
Updated to reflect the fact that a CCDS may be linked to more than one transcript. Hence need to add xrefs only once, i.e. check for existence before adding.

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