Add orthology mappings between S. lycopersicum and S. pennellii

So far, there are only genetic marker-based mappings (from SGN) available between the two tomato species. However, orthologous genes of _S. lycopersicum_  in other species are available via Ensembl Plants (Compara) in the platform. Alternatively, one could use the cross-refs to KEGG Orthology (KO) groups.