6.0.0

I'm extremely stupid and didn't commit as I go. To anyone reading this
I'm extremely sorry. A lot of these changes are very broad and I plan on
releasing Babel 6.0.0 today live on stage at Ember Camp London so I'm
afraid I couldn't wait. If you're ever in London I'll buy you a beer
(or assorted beverage!) to make up for it, also I'll kiss your feet and
give you a back massage, maybe.

packages/babel-core/test/path.js

@@ -8,11 +8,10 @@ suite("traversal path", function () {
     var expectCode = "function foo() {}";
 
     var actualCode = transform(expectCode, {
-      blacklist: "strict",
-      plugins: [new Plugin("foobar", {
+      plugins: [new Plugin({
         visitor: {
-          FunctionDeclaration: function () {
-            this.replaceWithSourceString("console.whatever()");
+          FunctionDeclaration: function (path) {
+            path.replaceWithSourceString("console.whatever()");
           }
         }
       })]