Move the node dependency to protobuf.d.ts from tests

protobuf/protobuf-tests.ts

@@ -1,5 +1,4 @@
 /// <reference path="protobuf.d.ts" />
-/// <reference path="../node/node.d.ts" />
 
 import ProtoBuf = require("protobufjs");
 

protobuf/protobuf.d.ts

@@ -3,6 +3,8 @@
 // Definitions by: Panu Horsmalahti
 // Definitions: https://github.com/borisyankov/DefinitelyTyped
 
+/// <reference path="../node/node.d.ts" />
+
 declare module ProtoBuf {
 	export interface IBuilder {
 		build: <T>() => T;