SwipeArea: fixed a bug were an unwanted clic event is sent

Signed-off-by: Christophe Chapuis <chris.chapuis@gmail.com>
SlidingItemArea: do not anchor the SwipeArea's position to the swiped item, only use initial positionning to prevent interfering with swipe computation

Signed-off-by: Christophe Chapuis <chris.chapuis@gmail.com>