import MGI background strain descriptions

We need to crawl and index the list of inbred mice strains (and substrains) from here:

http://www.informatics.jax.org/external/festing/mouse/STRAINS.shtml

Pull the prose descriptions, and pull each section. This will be tricky because it is screen scraping. But we will eventually be linking this to phenotype annotations that we create and load into another resource.

There is a similar one for rat, which i would also like to pull, if we get this one up and running:
http://www.informatics.jax.org/external/festing/rat/STRAINS.shtml