Merge pull request #176 from astrofrog/more-tests

pre-commit fixes

Added tests for MouseInteraction and ViewListener

Merge pull request #175 from astrofrog/line-test

pre-commit fixes

Added visual test for LineGL

Merge pull request #174 from astrofrog/fix-d3

Updated baseline images

Fix job to update visual references

Updated tests to improve visibility of selectors

Update package-lock.json

Added more contour tests as well as added selection tests

Pin d3 dependencies to stay consistent with bqplot

Update version to 1.9.1 and changelog [skip ci]

Merge pull request #172 from astrofrog/upgrade-node