add objectMode to node stream.WritableOptions

references #5658, references #5774

node/node-0.10.d.ts

@@ -1244,6 +1244,7 @@ declare module "stream" {
     export interface WritableOptions {
         highWaterMark?: number;
         decodeStrings?: boolean;
+        objectMode?: boolean;
     }
 
     export class Writable extends events.EventEmitter implements NodeJS.WritableStream {