Try babel/importloader for parceljs. More structure overhaul

config/plugins/visualizations/scatterplot/package.json

@@ -4,7 +4,6 @@
     "description": "Scatterplot visualization plugin for the Galaxy informatics framework",
     "main": " ",
     "scripts": {
-        "test": "test",
         "build": "parcel build src/scatterplot.js -d static/"
     },
     "keywords": [
@@ -15,10 +14,13 @@
     "author": "Carl Eberhard",
     "license": "BSD",
     "dependencies": {
+        "babel-plugin-auto-import": "^0.7.1",
+        "babel-preset-env": "^1.6.1",
         "backbone": "^1.3.3",
         "bootstrap": "^3.3.7",
         "d3": "^3.5.17",
         "jquery": "^3.2.1",
-        "jquery-ui-bundle": "^1.12.1"
+        "jquery-ui-bundle": "^1.12.1-migrate",
+        "underscore": "^1.8.3"
     }
 }