Add node modules and new code for release (#57)

Co-authored-by: taakleton <taakleton@users.noreply.github.com>

node_modules/underscore/modules/uniqueId.js

@@ -0,0 +1,7 @@
+// Generate a unique integer id (unique within the entire client session).
+// Useful for temporary DOM ids.
+var idCounter = 0;
+export default function uniqueId(prefix) {
+  var id = ++idCounter + '';
+  return prefix ? prefix + id : id;
+}