[deviantart] add support for all media types

- this includes
  - images
  - videos
  - flash-animations
  - journals

- also renamed some of the extractors
  - User  -> Gallery
  - Image -> Deviation

gallery_dl/text.py

@@ -136,6 +136,7 @@ else:
     clean_path = clean_path_posix
 
 unquote = urllib.parse.unquote
+escape = html.escape
 
 try:
     unescape = html.unescape