Defintions for musicmetadata package (#10841)

* Add Music Metadata

* Fix some errors

musicmetadata/musicmetadata-tests.ts

@@ -0,0 +1,10 @@
+/// <reference path="../node/node.d.ts" />
+/// <reference path="./musicmetadata.d.ts" />
+
+import * as fs from "fs";
+import * as mm from "musicmetadata";
+
+mm(fs.createReadStream("hype-train.mp3"), (err: Error, metadata: MM.Metadata) => {
+    if (err) throw err;
+    console.log(`Parsed song ${metadata.title}`);
+});

musicmetadata/musicmetadata.d.ts

@@ -0,0 +1,48 @@
+// Type definitions for musicmetadata 2.0.4
+// Project: https://www.npmjs.com/package/musicmetadata
+// Definitions by: Xavier Stouder <https://github.com/Xstoudi>
+// Definitions: https://github.com/DefinitelyTyped/
+
+/// <reference path="../node/node.d.ts" />
+
+declare module "musicmetadata" {
+    import {Readable} from "stream";
+    import {EventEmitter} from "events";
+
+    function mm(readStream: Readable, callback: (err: Error, metadata: MM.Metadata) => void): EventEmitter;
+    function mm(readStream: Readable, options: MM.Options, callback: (err: Error, metadata: MM.Metadata) => void): EventEmitter;
+
+    namespace mm { }
+
+    export = mm;
+}
+
+declare namespace MM {
+    export interface Options {
+        duration: boolean;
+        fileSize: number;
+    }
+
+    export interface Metadata {
+        artist: string[];
+        album: string;
+        albumartist: string[];
+        title: string;
+        year: string;
+        track: NoOf;
+        disk: NoOf;
+        genre: string;
+        picture: Picture[];
+        duration: number;
+    }
+
+    export interface NoOf {
+        no: number;
+        of: number;
+    }
+
+    export interface Picture {
+        format: string;
+        data: Buffer;
+    }
+}