edje: Apply color_class to TEXTBLOCK part's style

edje: Apply color_class to TEXTBLOCK part's style

Summary:
Applying color_class to TEXTBLOCK part's description will
change every color of textblock.
(Base text color, tag's color, colored emoticon's color and etc)

So, if we want to control only base text color using color_class,
color_class should modify color from textblock's style. Just like
text_class in textblock's style.

Test Plan:
1. Run elementary_test -to "entry"
2. Modify color fields and click "Apply" button.
3. See how entry's color is changed.

Reviewers: raster, cedric, tasn, herdsman, woohyun

Subscribers: akanad, z-wony, Blackmole, jpeg

Differential Revision: https://phab.enlightenment.org/D4283

@tizen_fix

Change-Id: I495d9ebb2d6ca603a3a3bf871466336d7a8cb1f3