Added tests for list_dbIDs and list_stable_dbIDs.
Added tests for list_dbIDs and list_stable_dbIDs.

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