SystemUI: Option to display Quick Settings when there are no ongoing notificaions

Added member function hasClearableNotifications to class
PhoneStatusBar. This function returns true when clearable
notifications are present on the status bar. Also, onTouchEvent in
NotificaionPanelView now flips to Quick Settings if there are no
ongoing notifications, and the QS_QUICK_PULLDOWN is set accordingly.

Change-Id: Ia77f90b19c7b408b7fc9376b6914e3173b734655
Add the option to make quick settings auto open