elm.hoversel: highlight selected item when auto update is enabled

elm.hoversel: highlight selected item when auto update is enabled

Summary:
When auto update is enabled, the label of the hoversel will be that of selected
item. This feature is usually used when changing state of something.
Highlighting item previous selected will show what is current state more
explicitly especailly hoversel has many items.

Test Plan: elementary_test -to hoversel

Reviewers: cedric, jpeg

Differential Revision: https://phab.enlightenment.org/D4799

Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>