efl_ui_textpath: introduce efl_ui_textpath_circular_set() interface.

efl_ui_textpath: introduce efl_ui_textpath_circular_set() interface.

Summary:
This patch revises efl_ui_textpath_circle_set() interface.

Current circle_set() behavior is wrongly working,
it makes object minimal size with (x * 2, y * 2).
Insanely, how big size if the object is far from the screen origin.

Secondly, current interface requires center position,
How this center position could be guranteed if user wants to put it into a container?

Third, actual textpath output could be out of the textpath boundary,
since the textpath is originated to middle of text height.
the display boundary can be outside of the textpath geometry by (half of text height).

All in all, put altogether in fix,
I confirmed there is no methods without any compatibility break.

This brings elm_textpath_circular_set() api introduced.

@feature

Reviewers: #committers, kimcinoo, jsuya

Subscribers: zmike, bu5hm4n, segfaultxavi, cedric, #reviewers, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D9260