RNAProduct: implement stable_id_version() and display_id()
RNAProduct: implement stable_id_version() and display_id()

muffato/ensembl,muffato/ensembl,Ensembl/ensembl,muffato/ensembl,james-monkeyshines/ensembl,james-monkeyshines/ensembl,Ensembl/ensembl,Ensembl/ensembl,james-monkeyshines/ensembl,james-monkeyshines/ensembl,Ensembl/ensembl,muffato/ensembl