The Great Migration: Create relational Schema

This schema describes the vcfs table, representing submitted vcfs and
associated metadata; genotypes, representing the calls in a given vcf
and associated information; and two annotations tables, to facilitate
annotation of regions and variants.
The great migration: Workers work

Add a `genotype_extractor` worker, which runs on submitted VCFs,
extracting the genotypes information and inserting it into the genotypes
table, as well as inserting the vcf and associated metadata into the
vcfs table.

Also updates old workers to use new shared code.
The great migration: update run validations
The great migration: add psycopg2 requirement
TGM: /runs view works with new schema
TGM: Add genotypes.py module as API to datastore
TGM: Javascript now works with new datastore

Update the RecordStore, pipe in data from genotypes.py via new views in
views.py.
TGM: Fix rebase issues.
TGM: Add test for VCF to CSV
TGM: Rework workers, address CR
TGM: Address CR
TGM: Address CR
TGM: Fix tests
Merge pull request #211 from hammerlab/move-to-relational-VCF-storage-and-backend-queries

Move to relational vcf storage and backend queries