CBG trends display selections

[krystophv]

Use the new display toggles from viz and track metrics.

[krystophv]

CGM Trends 1 - Add Checkboxes, default top/bottom off [dev: 5, tst: 1, ux: 1]

[krystophv]

Depends on: tidepool-org/viz#36

[krystophv]

ping @jebeck for review (or feel free to pass to next available person)

[jebeck]

I believe there are tests that should be updated...?

[krystophv]

@jebeck - I added tests for the tracking middleware as none previously existed. I think most of the rest of the changes are relying on having unit tests in the viz repo. I don't seem to be able to find any existing sets of tests that need updating. If you think it'd be a good opportunity to add in tests for the Footer or Modal components (which I don't think we have right now) then I can look into those.

[jebeck]

Tests on Footer would be good with the added complexity. Fine to leave Modal w/o tests. Thanks @krystophv!

[krystophv]

@jebeck - I think that's all the tests that needed updating/creating. This should be good for review again.

[jebeck]

Ditto here with another update from master because of the late merge of #368

[jebeck]

Thanks for the add of the totally missing tracking middleware tests!