* boards/images/scenery5_background.png: created. used by the hexagon board
	* boards/skins/default/config.png: remade in more easy to 'read'
	* boards/skins/default/difficulty_star.png: removed. replaced by some more cute one
	* boards/skins/default/difficulty_star1.png: some more cute icons for the difficulty
	* boards/skins/default/difficulty_star2.png:
	* boards/skins/default/difficulty_star3.png:
	* boards/skins/default/difficulty_star4.png:
	* boards/skins/default/difficulty_star5.png:
	* boards/skins/default/difficulty_star6.png:
	* src/boards/menu.c: (display_board_icon), (menu_create_item),
	(item_event), (create_info_area): removed the use of the rich text canvas cause it crashes
	* src/boards/python/algorithm.py: use the new scenery background with a bridge
	* src/gcompris/config.c: (gcompris_config_start),
	(display_difficulty_level): adjusted for the new difficulty icons
	* src/gcompris/gameutil.c: (gcompris_add_xml_to_data),
	(gcompris_display_difficulty_stars):  adjusted for the new difficulty icons
	* src/gcompris/gameutil.h: now give a ratio to gcompris_display_difficulty_stars