Adding Angular and dependent packages for testing

third_party/pkg/angular/playback_middleware/spec/playback_spec.js

+var playback = require('../lib/playback.js');
+
+describe('playback', function() {
+  it('should record a request and playback that request', function() {
+    var play = playback.playback();
+
+    play.record('request key', 'response data');
+
+    var output = play.playback();
+
+    expect(output).toContain('request key');
+    expect(output).toContain('response data');
+  });
+});