(ScrollView) Updates to scroll view internals to improve responsiveness and smoothnes...

(ScrollView) Updates to scroll view internals to improve responsiveness and smoothness of visual actions

[Problem] Overshoot indicator could occasionally remain on screen, overshoot would prevent panning in opposite direction until pan returned to point where overshoot started
[Solution] Replaced numerous constraints with property notifications.
           Implemented the new vector component animation to remove need for separate internal x/y components.
           First stage of constraint reduction on ScrollView, more to follow
           Pre clamp scroll value is now snapped back to clamped position using animation and no longer needs a constraint to follow old internal x/y components
           Made functionality of overshoot more solid by making it directly dependant on pre clamped scroll and post clamp scroll values now that animation is done elsewhere.
           Overshoot no longer instantly flicks back to 0 if user releases and restarts a gesture before values have finished animating back
           If a pan has locked to an axis it now remains locked if user releases and starts another pan before scrolling has completed, preventing issue where a vertical page scroll could be started in the middle of a horizontal page scroll, which brakes the appearance of all page scroll effects.

Change-Id: I73e8ca71f5ffd8eb3c8a1fbf91823881ac4bb2ce
Signed-off-by: Julien Heanley <j.heanley@partner.samsung.com>