Correct the throw()'n messages in some of the abstract methods. Nicify code and comments of the methods at the end.
Correct the throw()'n messages in some of the abstract methods.
Nicify code and comments of the methods at the end.

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