Merge pull request jashkenas#988 from sdemjanenko/fix_bindAll_doc

Fix _.bindAll documentation to note that methodNames are required

index.html

@@ -956,8 +956,7 @@ <h2 id="functions">Function (uh, ahem) Functions</h2>
         <b>methodNames</b>, to be run in the context of that object whenever they
         are invoked. Very handy for binding functions that are going to be used
         as event handlers, which would otherwise be invoked with a fairly useless
-        <i>this</i>. If no <b>methodNames</b> are provided, all of the object's
-        function properties will be bound to it.
+        <i>this</i>. <b>methodNames</b> are required.
       </p>
       <pre>
 var buttonView = {