genlist: Fixed broken genlist item focus support.
genlist: Fixed broken genlist item focus support.

Now it works so much better than before.
- Fixed the separate behavior between selected item and focused item.
- Fixed wrong focus set when genlist is focused first time by mouse.
- Fixed wrong scroll movement when the focus highlight is disabled.
- Item selection sets that item focused. So when an item is selected, do
not need to set the focus again.
- Fixed wrong call for _elm_genlist_item_content_focus_set on deleted
item.

tasn/elementary,tasn/elementary,rvandegrift/elementary,tasn/elementary,tasn/elementary,FlorentRevest/Elementary,FlorentRevest/Elementary,rvandegrift/elementary,FlorentRevest/Elementary,tasn/elementary,FlorentRevest/Elementary,rvandegrift/elementary,rvandegrift/elementary