Reviewed audio issues

- Updated dr_mp3 and implemented it
- Reviewed sampleCount vs frameCount
- Reviewed XM playing (some weird things...)

examples/audio/audio_music_stream.c

@@ -59,6 +59,8 @@ int main()
         
         // Get timePlayed scaled to bar dimensions (400 pixels)
         timePlayed = GetMusicTimePlayed(music)/GetMusicTimeLength(music)*400;
+        
+        if (timePlayed > 400) StopMusicStream(music);
         //----------------------------------------------------------------------------------
 
         // Draw