Summary:
The mixin encapsulates the correct
- creation
- composition attaching
- Lifecycle handling
of the focus managers that are assosiated with the object.
This fixes error messages on shutdown, and additionally lifetime issues
where the composite_attached object was deleted before the object was
deleted.
Reviewers: cedric, zmike
Reviewed By: zmike
Subscribers: segfaultxavi, zmike
Tags: #efl
Differential Revision: https://phab.enlightenment.org/D6108