According to user tests, users have a hard time finding out how to
edit links. Thus, add same system as image edition (a small button
appearing when hovering the element).
Extract and unify these two to avoid redundancies between handlings as
they are broadly similar (only details such as label, positioning and
size of button relative to the element being hovered really change,
the lifecycle itself is the same).
The main setup still isn't very clean, there might be a better way to
do it.
bzr revid: xmo@openerp.com-20131204105212-u0a49nbvwilgtfst
Xavier Morel
b79e56d1af