Remove debugging line
Merge pull request #208 from ENCODE-DCC/439-facet-expand

Remove debugging line
Use ignored underscore properties in test data to for expected results.
flake8 cleanup; make test_post_duplicate actually test stuff.
Merge branch 'edw-test-cleanup'
Further tidy up of test_edw_sync
New model for popovers, pushed up to App.js, and using React context.