New upstream release 1.53
    
    - Fixing set_multi() so that if the server closes the connection it will no
      longer raise AttributeError
    - readline() now will mark the connection dead if the read fails
    - Changing check_keys to use re.match() instead of str.translate(), because
      re.match() works with Python < 2.6
    - Add a MANIFEST.in file
    - Client() now takes a "check_keys" option, which defaults to True
    - Converting control character checking of keys based on performance testing of
      alternatives
    - Converted unicode tests from using u''
    - Doing a "set" after server goes away, raised AttributeError: 'NoneType'
      object has no attribute 'sendall'
    - incr/decr return None instead of 0 on server connection failure
    - Supports IPv6 connections using: "inet6:[fd00::32:19f7]:11000"