Edje_Edit: support new edje top block "text classes" with edje_edit API

Edje_Edit: support new edje top block "text classes" with edje_edit API

Plenty of new API:
edje_edit_text_classes_list_get - to return total list of text_classes inside of
loaded collection of groups
edje_edit_text_class_add - add new text class into loaded collection
edje_edit_text_class_del - deleting
edje_edit_text_class_name_set - renaming existing text class into something new
edje_edit_text_class_font_{get|set} - get/set font name
edje_edit_text_class_size_{get|set} - get/set font size