* TODO: removed train goes faster and arrow issue cause its fixed.
* boards/dataset/mrpatate.xml: added much more images. Now uses imageset.
* boards/watercycle.xml.in: changed help text
* src/boards/python/watercycle.py: little cleanup
* src/boards/read_colors.c: (start_board), (end_board): memory leak: added g_list_free
  where needed
  * src/gcompris/images_selector.c: (gcompris_images_selector_start),
  (gcompris_images_selector_stop), (display_image),
  (display_image_set), (free_stuff), (item_event_imageset_selector),
  (parseImage), (parse_doc), (read_xml_file): complete rework to support dataset in the xml
   file and display them.