Merge pull request #3404 from jt000/master

Adding direct error manipulation methods to ko validation

knockout.validation/knockout.validation.d.ts

@@ -143,6 +143,9 @@ interface KnockoutSubscribableFunctions<T> {
     isValidating: KnockoutObservable<boolean>;
     rules: KnockoutObservableArray<KnockoutValidationRule>;
     isModified: KnockoutObservable<boolean>;
+    error: KnockoutComputed<string>;
+    setError(error: string): void;
+    clearError(): void;
 }
 
 declare module "knockout.validation" {