[deviantart] adjust default paths

- user.deviantart.com/(gallery|favourites|journal)/ images go into
  * <user>/
  * <user>/Favourites/
  * <user>/Journal/
  (having an extra "Gallery" folder for a user's gallery-images seems
   a bit too much if these are all you want to download, which is
   probably the default use-case)

- single "deviations" (user.deviantart.com/(art|journal)/name-123) go
  into their owner's directory:
  * <user>/
  (putting them into their own directory seems weird in practice)

test/test_extractors.py

@@ -54,7 +54,7 @@ skip = [
     # don't work on travis-ci
     "exhentai", "kissmanga", "mangafox", "dynastyscans", "nijie",
     # temporary issues
-    "turboimagehost", "twitter",
+    "fallenangels",
 ]
 # enable selective testing for direct calls
 if __name__ == '__main__' and len(sys.argv) > 1: