bugfix: self-alignments are expected to have the same species twice
bugfix: self-alignments are expected to have the same species twice

but we need some specific code to handle them

Ensembl/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara