stricter ECMA5 compliance. _.every now requires an iterator to be passed. #160

underscore.js

@@ -168,7 +168,6 @@
   // Delegates to **ECMAScript 5**'s native `every` if available.
   // Aliased as `all`.
   _.every = _.all = function(obj, iterator, context) {
-    iterator || (iterator = _.identity);
     var result = true;
     if (obj == null) return result;
     if (nativeEvery && obj.every === nativeEvery) return obj.every(iterator, context);