handle images served from directory + svg content type

https://anki.tenderapp.com/discussions/ankidesktop/41974-win-linux-when-pasting-some-html-i-get-error-in-_run_command-ankirsbackendioerror-ioerror

pylib/anki/media.py

@@ -112,6 +112,7 @@ class MediaManager:
             type_map = {
                 "image/jpeg": ".jpg",
                 "image/png": ".png",
+                "image/svg+xml": ".svg",
             }
             if content_type in type_map:
                 fname += type_map[content_type]

qt/aqt/editor.py

@@ -837,6 +837,8 @@ to a cloze type first, via Edit>Change Note Type."""
         # strip off any query string
         url = re.sub(r"\?.*?$", "", url)
         fname = os.path.basename(urllib.parse.unquote(url))
+        if not fname.strip():
+            fname = "paste"
         if content_type:
             fname = self.mw.col.media.add_extension_based_on_mime(fname, content_type)