elementary - modified content_set/get/unset part names to be simple names.

elementary - modified content_set/get/unset part names to be simple names.

Previous part names are just the swallow part names
but in modified version, the part names chaned to simpler meaning names to use.

i.e for button

elm_object_content_part_set(button, "elm.swallow.icon", icon);
-> elm_object_content_part_set(button, "icon", icon);

git-svn-id: svn+ssh://svn.enlightenment.org/var/svn/e/trunk/elementary@65295 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33