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

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

node_modules/underscore/amd/_flatten.js

@@ -0,0 +1,32 @@
+define(['./_getLength', './_isArrayLike', './isArray', './isArguments'], function (_getLength, _isArrayLike, isArray, isArguments) {
+
+  // Internal implementation of a recursive `flatten` function.
+  function flatten(input, depth, strict, output) {
+    output = output || [];
+    if (!depth && depth !== 0) {
+      depth = Infinity;
+    } else if (depth <= 0) {
+      return output.concat(input);
+    }
+    var idx = output.length;
+    for (var i = 0, length = _getLength(input); i < length; i++) {
+      var value = input[i];
+      if (_isArrayLike(value) && (isArray(value) || isArguments(value))) {
+        // Flatten current level of array or arguments object.
+        if (depth > 1) {
+          flatten(value, depth - 1, strict, output);
+          idx = output.length;
+        } else {
+          var j = 0, len = value.length;
+          while (j < len) output[idx++] = value[j++];
+        }
+      } else if (!strict) {
+        output[idx++] = value;
+      }
+    }
+    return output;
+  }
+
+  return flatten;
+
+});