Added ability to define core database via host, user, dbname and port.
Added ability to define core database via host, user, dbname and port.

etapanari/ensembl-compara,Ensembl/ensembl-compara,danstaines/ensembl-compara,ckongEbi/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara,dbolser-ebi/ensembl-compara,Ensembl/ensembl-compara,kumarsaurabh20/ensembl-compara,Ensembl/ensembl-compara,kumarsaurabh20/ensembl-compara,etapanari/ensembl-compara,danstaines/ensembl-compara,danstaines/ensembl-compara,ckongEbi/ensembl-compara,dbolser-ebi/ensembl-compara,danstaines/ensembl-compara,ckongEbi/ensembl-compara,kumarsaurabh20/ensembl-compara,kumarsaurabh20/ensembl-compara,etapanari/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara,etapanari/ensembl-compara,dbolser-ebi/ensembl-compara,danstaines/ensembl-compara,Ensembl/ensembl-compara