DISCO: add new resource dbGaP

The resource dbGaP seems like a really important resource, with lots of genotype-phenotype data. I think the phenotypes/traits are MeSH headings.

The "good" data, which actually allows us to look at full genomic-phenotypic profiles, is not allowed to be accessible on "the internet":
https://dbgap.ncbi.nlm.nih.gov/aa/wga.cgi?page=login, but I think it might be really useful for our analysis.

So, I think we should try to take whatever is publicly available. If you go to http://www.ncbi.nlm.nih.gov/projects/gapplusprev/sgap_plus.htm, and let everything be selected to "all", and download the result, I think you'll get all genno-phenos.

I wonder, however, if there is a way we could/should use the more-complete data offline, to assist with our scoring system?