SystemUI: Re-adjust signal strength icons

Change-Id: Id6dad0800e5e15ec694b24ecb9a88ccc0d4771d8
    Improve scrolling cache

    Scrolling cache helps make short scrolls/flings smooth but will
    cause stutter when long flings are made. This patch disables
    scrolling cache when long flings are made.

    This patch also fixes a related bug where scrolling cache will
    not be enabled properly when transitioning from flinging to scrolling.

    Patch Set 2: Calculate threshold based on maximum velocity (Sang Tae Park)

    Credits: Pawit Pornkitprasan

Change-Id: Iad52a35120212c871ffd35df6184aeb678ee44aa
framework:Thread synchronization for UI update

Issue : Framework reboot was observed due to out of sync between
        two threads which inturn causes Null pointer exception
        while updating airplanemode.
Fix : Handled Null pointer exception and the crash is not observed.
CRs-Fixed: 570122

Change-Id: I2e969f6e7726ffcf8648b366ebb54cb2b0afc292
SystemUI: PhoneStatusBarView: disable DEBUG_GESTURES

Change-Id: I3911c464d1f008ac2c96a1104761007fad41a3ae
Signed-off-by: Roman Birg <roman@cyngn.com>
SystemUI: add Settings.System toggle for quick-quick settings pulldown

Change-Id: I3c5dcfc23f39bf8be6c402e25f61e6f57a8add2c
Signed-off-by: Roman Birg <roman@cyngn.com>
SystemUI: double tap to sleep improvements

* Make it more reliable
* Add it to keyguard
* Add a content observer to not always query Settings.System on every
touch event

Change-Id: I292c4d9d9f810843590b7a9ec6e15b99ac44009d
Signed-off-by: Roman Birg <roman@cyngn.com>