In build_overlap_scores(): Only add target if $add_target is non-zero, just as is done for adding source.
In build_overlap_scores(): Only add target if $add_target is non-zero,
just as is done for adding source.

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