DISCO: import phenotype-related variation data from ensembl

Pull all variation data from ensembl, with a preference for the phenotype-related variants. This data is needed in order to build a geno-pheno browser.

Note that the phenotypes in ENSEMBL are only text-based, with no identifiers, and will need to somehow be mapped. It looks like the labels are simply the OMIM ids, but probably can be mapped to the uber-disease id whenever it is finally ingested by ontoquest.

This can be achieved with the Variation API:

http://uswest.ensembl.org/info/docs/api/variation/variation_tutorial.html#connect

making a file with the ph_variants variation set:
http://uswest.ensembl.org/info/docs/variation/data_description.html#variation_sets

Make sure to get the following:
1. genomic locations (to feed to jbrowse)
2. phenotype
3. any genes linked
4. synonyms
5. evidence trail?