Updated the style of the examples

* const/let instead of var
* classes
* pass our own eslint checks

lib/jasmine-core/example/spec/PlayerSpec.js

@@ -1,34 +1,34 @@
-describe("Player", function() {
-  var player;
-  var song;
+describe('Player', function() {
+  let player;
+  let song;
 
   beforeEach(function() {
     player = new Player();
     song = new Song();
   });
 
-  it("should be able to play a Song", function() {
+  it('should be able to play a Song', function() {
     player.play(song);
     expect(player.currentlyPlayingSong).toEqual(song);
 
-    //demonstrates use of custom matcher
+    // demonstrates use of custom matcher
     expect(player).toBePlaying(song);
   });
 
-  describe("when song has been paused", function() {
+  describe('when song has been paused', function() {
     beforeEach(function() {
       player.play(song);
       player.pause();
     });
 
-    it("should indicate that the song is currently paused", function() {
+    it('should indicate that the song is currently paused', function() {
       expect(player.isPlaying).toBeFalsy();
 
       // demonstrates use of 'not' with a custom matcher
       expect(player).not.toBePlaying(song);
     });
 
-    it("should be possible to resume", function() {
+    it('should be possible to resume', function() {
       player.resume();
       expect(player.isPlaying).toBeTruthy();
       expect(player.currentlyPlayingSong).toEqual(song);
@@ -36,7 +36,7 @@ describe("Player", function() {
   });
 
   // demonstrates use of spies to intercept and test method calls
-  it("tells the current song if the user has made it a favorite", function() {
+  it('tells the current song if the user has made it a favorite', function() {
     spyOn(song, 'persistFavoriteStatus');
 
     player.play(song);
@@ -46,13 +46,13 @@ describe("Player", function() {
   });
 
   //demonstrates use of expected exceptions
-  describe("#resume", function() {
-    it("should throw an exception if song is already playing", function() {
+  describe('#resume', function() {
+    it('should throw an exception if song is already playing', function() {
       player.play(song);
 
       expect(function() {
         player.resume();
-      }).toThrowError("song is already playing");
+      }).toThrowError('song is already playing');
     });
   });
 });