Provide wl_output events on hotplug
Provide wl_output events on hotplug

Summary:
Clients that have bound wl_output now receive wl_output events on hotplug

NOTE: We don't handle removal yet

Reviewers: devilhorns, zmike

Reviewed By: devilhorns, zmike

Subscribers: cedric

Maniphest Tasks: T2131

Differential Revision: https://phab.enlightenment.org/D2008

rvandegrift/e,tizenorg/platform.upstream.enlightenment,tizenorg/platform.upstream.enlightenment,tizenorg/platform.upstream.enlightenment,FlorentRevest/Enlightenment,FlorentRevest/Enlightenment,rvandegrift/e,rvandegrift/e,tasn/enlightenment,tasn/enlightenment,tasn/enlightenment,FlorentRevest/Enlightenment