Merge pull request #3429 from nlundquist/patch-1

Export ViewModel and CollectionObservable

knockback/knockback.d.ts

@@ -163,6 +163,8 @@ declare module Knockback {
     }
 
     interface Static extends Utils {
+    	ViewModel;
+    	CollectionObservable;
         collectionObservable(model?: Backbone.Collection<Backbone.Model>, options?: CollectionOptions): CollectionObservable;
     	/** Base class for observing model attributes. */
     	observable(