Shim moment types with MomentFormatSpecification

Fixes compatibility issue with moment-timezone types.

Author: KorinaGraber

typings/moment.d.ts

@@ -0,0 +1,7 @@
+import * as moment from "moment";
+
+declare module "moment" {
+    export type MomentFormatSpecification = string;
+}
+
+export = moment;