correct typo added test for 'fetch_all_by_feature_class' with density features
correct typo
added test for 'fetch_all_by_feature_class' with density features

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