Added the underscore node_module.

node_modules/underscore/modules/memoize.js

@@ -0,0 +1,13 @@
+import has from './_has.js';
+
+// Memoize an expensive function by storing its results.
+export default function memoize(func, hasher) {
+  var memoize = function(key) {
+    var cache = memoize.cache;
+    var address = '' + (hasher ? hasher.apply(this, arguments) : key);
+    if (!has(cache, address)) cache[address] = func.apply(this, arguments);
+    return cache[address];
+  };
+  memoize.cache = {};
+  return memoize;
+}