Extend SwipeHelper to support vertical gestures

This commit was Re-committed by @namja in Triangles

* Un-hardcode CONSTRAIN_SWIPE and FADE_OUT_DURING_SWIPE, define
  through proper callback, per-layout
* Up (GESTURE_NEGATIVE) and down (GESTURE_POSITIVE), mostly needed
  by new Hover hide /w swipe up gesture

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>
Change-Id: I68c42a8ccabca73a1b241ba7cf264db9c912fccd

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