[E-devel] [patch] elm_scroller - add gravity functionality

[Hyoyoung C. <hyo...@sa...>]

Dear developers.

I made a gravity features for stopping scroller.
Elm_scroller's fixed when child's growing lower.
However if scroller's child is growing upper,  
the elm_scroller always moving and waving to upper direction.
Because elm_scroller sets internal pan to keep current virtual position.
Gravity functions introduce to stopping scroller.

@doc
* It set scrolling gravity. It adds scrolling weight values
    * to the scroller. Usually it uses for stopping the scroller.
    * To set y as 0.0 for lower growing child objects,
    * even though child objects are added to bottom, the scroller doesn't
move.
    * To set y as 1.0 for upper growing child objects. And x is horizontal
gravity.
    * By default 0.0 for x and y.
@doc

Thank you.