PhoneStatusBarView: only get double tap gesture listener if the feature is enabled

this is a MUCH better way to do things since this feature is sloppy dildos anyways

Change-Id: Ifc0bff2db00b884dbfdfbf72b1c552dc4f185f6d

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java
FB: DoubleTab2Sleep stopped working propperly
after a boot or sometime when you changed something on statusbar or quicksettings, DT2S stopped working
You have to uncheck and then check the checkbox for it in settings to make it work again
This is because the code would only be executed when the setting actually has changed (OnChange) but not on boot or on RebuildStatusBar

PS:
Set mDoubleTapToWake back to false so it will be sure the GestureDetector will be created
PS3: only add a gesture listener if it's null and mDoubleTab... -> mDoubleTap...  -PrimeDirective

Change-Id: I44f5f1185d8a8ead4b7678c1ebec420f05a16e85

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java