Merge pull request #203 from Gallaecio/safe-url-extra-escaping

safe_url_string: escape additional characters

Author: kmike

.flake8

@@ -10,4 +10,5 @@ ignore =
     W504,
 
     # black disagrees with flake8, and inserts whitespace
-    E203,  # whitespace before ':'
+    # E203: whitespace before ':'
+    E203,