issue #8918 \emoji does not support emoji with ZWJ

- added new items to the list (of GitHub) supported
- created compatibility code for items not supported anymore by GitHub
- corrected codes for items to represent current standard
- added new items to test
- adjusted documentation, i.e. made sure directory is present before download of images

doc/emojisup.doc

@@ -60,6 +60,8 @@ def get_emojis():
     return json.loads(raw_data)
 
 def download_images(dir_name):
+    if not os.path.exists(dir_name):
+        os.makedirs(dir_name)
     json_data = get_emojis()
     num_items = len(json_data)
     cur_item=0