SGViewController  & SGSettingsViewController & SGAudioModule and many...

//SGViewController
1. Separate changeBackground and changeCG method, both method search
resources in different folders.
2. Add changeCharacterImage method.
3. Add music control function, start and stop.
4. Segue methods for sending and receiving data from
SGSettingsViewController.
5. Add delegate methods for SGSettingsViewController, using for change
dialog box transparency and CG display mode.

//SGSettingsViewController
1. Create delegate protocol for real time changing settings.
2. Add methods for saving current settings when unwind; and restore
previous saved settings when modal.
3. Add dialogBoxOpaqueSlider, bgmVolumeSlider, voiceVolumeSlider, and
cgModeSwitch.

//SGAudioModule
1. Add two volume properties, and set players’ volume in setter.
2. Add delegate for volume changing in SGSettingsViewController.
3. Separate BGM folder and Voice folder.

//Generic
1. New resource file structure.
2. Modification in Storyboard.
3. Some test methods.
4. New assets.