[2/2] settings: volume tweaks

Setting to disable volume adjust sounds (VOLUME_ADJUST_SOUNDS_ENABLED)
This is so annoying :)

Enhanced dialog to add checkbox for unlinking ringer and
notification volume (VOLUME_LINK_NOTIFICATION)

some minor code style issues fixed + always use onchange listener
onclick is depreciated even if google still uses it....but
we can go with actual API

Change-Id: Ia30bbb1c2f44d0c21cd08748bd552685810f960f