Move to ES6 module definition style.

Author: aleung

field/field-test.ts

@@ -1,6 +1,7 @@
 // From https://github.com/jprichardson/field/blob/e968fd979ba1a06e35571695ddfdad513e516eae/README.md
 
 /// <reference path="field.d.ts" />
+import * as field from 'field';
 
 // get
 

field/field.d.ts

@@ -3,7 +3,7 @@
 // Definitions by: Leo Liang <https://github.com/aleung/DefinitelyTyped>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
-declare module field {
+declare module 'field' {
     export function get(topObj: any, fields: string): any;
     export function set(topObj: any, fields: string, value: any): any;
 }