This fixes two issues with the caching on Windows:

* the cache directory should really be %LOCALAPPDATA%
 * ~ is not a meaningful directory on Windows. It should really be
   os.path.expanduser('~'). To be honest it is probably always safe to
   assume that os.getenv('LOCALAPPDATA') executes to something sensible
   on any Windows system that hasn't been tampered with.

AUTHORS.txt

@@ -57,6 +57,7 @@ Code Contributors
 - Tim Gates (@timgates42) <tim.gates@iress.com>
 - Lior Goldberg (@goldberglior)
 - Ryan Clary (@mrclary)
+- Max Mäusezahl (@mmaeusezahl) <maxmaeusezahl@googlemail.com>
 
 And a few more "anonymous" contributors.