Fix bugs in note controller being removed

scripts/NoteController.gd

@@ -13,7 +13,8 @@ func _ready():
 
 func button_pressed():
 	NotePlayer.stream = NoteAudio
-	NotePlayer.play()
+	if !NotePlayer.playing:
+		NotePlayer.play()
 
 func chord_changed(chord):
 	var resource_string = "res://audio/%s/%s%s.ogg" % [chord, chord, self.name]

scripts/StopController.gd

@@ -7,10 +7,10 @@ var NotePlayer: AudioStreamPlayer
 func _ready():
 	RhythmPlayer = get_node("/root/Control/RhythmPlayer")
 	ChordPlayer = get_node("/root/Control/ChordPlayer")
-	NotePlayer = get_node("/root/Control/NotePlayer")
 	self.pressed.connect(button_pressed)
 
 func button_pressed():
-	RhythmPlayer.stop()
-	ChordPlayer.stop()
-	NotePlayer.stop()
+	if RhythmPlayer.playing:
+		RhythmPlayer.stop()
+	if ChordPlayer.playing:
+		ChordPlayer.stop()