First steps of &JSRef -> JSRef conversion

Replace &JSRef with JSRef in the bulk of the generated code. This will
remove a level of indirection throughout all DOM code.

This patch doesn't change methods implemented on JSRef<T> to take `self`
rather than `&self`, and it leaves a few other uses of &JSRef, but those
changes can be made incrementally.

components/script/dom/workernavigator.rs

@@ -23,9 +23,9 @@ impl WorkerNavigator {
         }
     }
 
-    pub fn new(global: &JSRef<WorkerGlobalScope>) -> Temporary<WorkerNavigator> {
+    pub fn new(global: JSRef<WorkerGlobalScope>) -> Temporary<WorkerNavigator> {
         reflect_dom_object(box WorkerNavigator::new_inherited(),
-                           &Worker(*global),
+                           &Worker(global),
                            WorkerNavigatorBinding::Wrap)
     }
 }