Added module Elm_hoversel.
Added elm_hoversel_add.
Added elm_hoversel_horizontal_set/get.
Added elm_hoversel_hover_parent_set/get.
Added elm_hoversel_begin/end/expandable_get/clear.
Added elm_hoversel_items_get/item_add.
Added elm_hoversel_item_icon_set/get.
Added events in module Elm_hoversel.
Addex example hoversel_example_01.ml