Summary:
There are 2 ways to toogle the panel, by using elm_panel_toggle API and by interaction such as flick or click on panel.
This toggled event can help us to know the time when the panel toggled by all case.
Reviewers: woohyun, kimcinoo, Hermet, jypark
Subscribers: cedric, jpeg
Differential Revision: https://phab.enlightenment.org/D4180