SGAnimationToSettings & SGViewController

1. Custom modal transition.
2. Transparency settings page.
SGAudioModule & SGCommandFormatter & SGViewController

//SGAudioModule
1. Merge all players into one dispatch queue.

//SGCommandFormatter
1. Add default value to the image changing methods.

//SGViewController
1. Image changing and background color changing are able to set
transition time.
2. Put image changing Transition Style maker into DEFAULT queue.
3. Pure color background accept hex value color. (Only hex color)