Cache: Unicode URI will cause exception when creating cache key

[yourabi]

If a URI is requested with unicode characters a UnicodeEncodeError is thrown

backends.py lines 131 (read)
versioned_key = hashlib.md5(key_version + "_" + key).hexdigest()

HttpBackend line 70 (fetch)
cache_tuple = self.cache.read(self.request.source)

Example (Before and After django smart_str)
Alton Auto Daylight Savings ™ Wall Clock
Alton Auto Daylight Savings %E2%84%A2 Wall Clock
Alton Auto Daylight Savings \xe2\x84\xa2 Wall Clock