Fix #188 by Tien Vo: Introduce at_icon(), support font-awesome by default.
Entity template: Return error message instead of silently failing.
at_icon(): Support fontello sets.
Merge branch 'dev-master' into site/crom

* dev-master:
  at_icon(): Support fontello sets.
  Entity template: Return error message instead of silently failing.
  Fix #188 by Tien Vo: Introduce at_icon(), support font-awesome by default.

Conflicts:
	lib/Helper/Content_Render.php