Added the underscore node_module.

node_modules/underscore/cjs/_cb.js

@@ -0,0 +1,12 @@
+var underscore = require('./underscore.js');
+var _baseIteratee = require('./_baseIteratee.js');
+var iteratee = require('./iteratee.js');
+
+// The function we call internally to generate a callback. It invokes
+// `_.iteratee` if overridden, otherwise `baseIteratee`.
+function cb(value, context, argCount) {
+  if (underscore.iteratee !== iteratee) return underscore.iteratee(value, context);
+  return _baseIteratee(value, context, argCount);
+}
+
+module.exports = cb;