Update underscore.js to 1.13.6

vendor/underscore/modules/map.js

@@ -0,0 +1,16 @@
+import cb from './_cb.js';
+import isArrayLike from './_isArrayLike.js';
+import keys from './keys.js';
+
+// Return the results of applying the iteratee to each element.
+export default function map(obj, iteratee, context) {
+  iteratee = cb(iteratee, context);
+  var _keys = !isArrayLike(obj) && keys(obj),
+      length = (_keys || obj).length,
+      results = Array(length);
+  for (var index = 0; index < length; index++) {
+    var currentKey = _keys ? _keys[index] : index;
+    results[index] = iteratee(obj[currentKey], currentKey, obj);
+  }
+  return results;
+}