DISCO: import orthologies from ENSEMBL

We should import the homology/paralogy from ensembl for whatever pair-wise organisms we ingest.

Here's a description of their method:
http://uswest.ensembl.org/info/docs/compara/homology_method.html

I think this data is available via their API, so we'll have to use that and write a script to pull it in.

Initial species to include are: Human, Mouse, Fish, Fly, Worm (our core). Then Rat. Then, expand to the species that are in OMIA.