Merge pull request #384 from hammerlab/issue-350-download-vcf

Can now download VCFs, major code cleaning as well
Adding user comments with CRUD operations and markdown
Moving comment test data into the new test data directory
Addressing code review comments
Minor rename for clarity
Fix typo in index worker
Don't assume bai.json errors are 'Not Found'
Merge pull request #404 from hammerlab/json-bai

Make BAI indexing work again
Changing last_modified_us name, and a few smaller changes
Removing unnecessary import
Disabling pylint in the right place
Merge pull request #387 from hammerlab/add_user_comments_rebased

Adding user comments with CRUD operations and markdown
Display true positive indication in the table
Address CR
Change comment UI + add icons for comments

Darken table rows