Settings: LiquidSmooth Sound options

added safe headset volume and less annoying sound notification there

Change-Id: I8ab4f4b9ec320238b05ac51fb76ac24b93c37d37

Conflicts:
        modified:   res/values/attrs.xml
        modified:   res/values/cm_strings.xml
        modified:   res/xml/appgroup_list.xml
        new file:   res/xml/liquid_sound_settings.xml
        modified:   res/xml/notification_settings.xml
        new file:   src/com/android/settings/SoundSettings.java