Backport werkzeug 2.0 support

Index: setup.py
--- setup.py.orig
+++ setup.py
@@ -108,7 +108,7 @@ setup(name=name,
         'python-dateutil',
         'polib',
         'python-sql >= 0.5',
-        'werkzeug < 1.0',
+        'werkzeug',
         'wrapt',
         'passlib >= 1.7.0',
         ],
