Adds Lyrics Support to Subsonic API (#1379)

* Add function 'isSynced' that identifies if lyrics are synced or not and add tests for the same

* implement 'getLyrics' which returns lyrics if they exist

Signed-off-by: Dheeraj Lalwani <lalwanidheeraj1234@gmail.com>

* remove timestamps frorom the the lyrics if they are synced, fix filters & clean up code

Signed-off-by: Dheeraj Lalwani <lalwanidheeraj1234@gmail.com>

* add snapshot tests for the 'Lyrics' response & add some clean up

Signed-off-by: Dheeraj Lalwani <lalwanidheeraj1234@gmail.com>

* add tests for 'GetLyrics' function

Signed-off-by: Dheeraj Lalwani <lalwanidheeraj1234@gmail.com>

* update the snapshot test & the test for 'GetLyrics' function

Signed-off-by: Dheeraj Lalwani <lalwanidheeraj1234@gmail.com>

server/subsonic/responses/responses_test.go

@@ -561,4 +561,37 @@ var _ = Describe("Responses", func() {
 			})
 		})
 	})
+
+	Describe("Lyrics", func() {
+		BeforeEach(func() {
+			response.Lyrics = &Lyrics{}
+		})
+
+		Context("without data", func() {
+			It("should match .XML", func() {
+				Expect(xml.Marshal(response)).To(MatchSnapshot())
+			})
+			It("should match .JSON", func() {
+				Expect(json.Marshal(response)).To(MatchSnapshot())
+			})
+		})
+
+		Context("with data", func() {
+			BeforeEach(func() {
+				response.Lyrics.Artist = "Rick Astley"
+				response.Lyrics.Title = "Never Gonna Give You Up"
+				response.Lyrics.Value = `Never gonna give you up
+				Never gonna let you down
+				Never gonna run around and desert you
+				Never gonna say goodbye`
+			})
+			It("should match .XML", func() {
+				Expect(xml.Marshal(response)).To(MatchSnapshot())
+			})
+			It("should match .JSON", func() {
+				Expect(json.Marshal(response)).To(MatchSnapshot())
+			})
+
+		})
+	})
 })