abstractDrawer underscore
arcDrawer underscored
areaDrawer underscored
elementDrawer underscored
lineDrawer underscored
rectDrawer underscored
Use _datasetKeysInOrder to mandate order
Adding test
Set default radius for hover target.

Close #1375.
Release version 0.38.0
Merge pull request #1420 from palantir/underscoreUnexposedDrawer

[Drawer] - Underscore unexposed variables
Merge pull request #1423 from palantir/release-v0.38.0

Release version 0.38.0 (--> develop)
Fix extending domainer and update tests.

Close #1424.
Merge pull request #1418 from palantir/radius

Set default radius for hover target.
Merge pull request #1425 from palantir/fix_domainer

Fix extending domainer and update tests.
Merge pull request #1409 from palantir/scaleExtentOrder

[AbstractPlot] - Updating scale extent obeys dataset key ordering
Merge branch 'develop' into unifyBarPlot