Don't show the miniview by default

This object will be swallowed into the theme and that's how its
visibility should be controlled. But in the case that the user's theme
doesn't have the right part, we are left with a dangling object floating
in a corner and visible when it shouldn't be.
theme: align transparency msg formatting with default theme
themes: remove edje_cc warning by adding ellipsis: -1;

Reviewers: billiob, Sachiel, raster

Differential Revision: https://phab.enlightenment.org/D1218
media: improve media control pos/vol slider

Summary:
currently, pos/vol could be changed by using only knob not slider area.
use slider area as event source, and control knob internally.

Fixes T1440

Test Plan: terminology -> tycat video file -> try to control pos/vol by clicking slider area

Reviewers: billiob

Subscribers: seoz

Maniphest Tasks: T1440

Differential Revision: https://phab.enlightenment.org/D1219