Blowfish and AES FiSH like for X-Chat in 100% Python

Requirements: PyCrypto, and Python 2.5+

Copyright 2011 Emiliano A. Gonzalez http://www.ergio.com.ar
Based in works of Nam T. Nguyen (FiSH clone) and Bjorn Edstrom (cryptographic methods for IRC)
Released under GPLV3 license

Changelog:
    * 1.0:
        + Initial release AES256CBC from PyCrypto

DESCRIPTION:
    Based on the original - de facto standard - FiSH encryption for IRC: http://fish.secure.la/
    This version add some features that make original system more secure.
        - At close or unload plugin, the passwords are saved ONLY if is setted a key file password.
        - Messages are automatically unencrypted in all modes.
        - Nicks ends in when messages are:
            +   : AES256CBC
            -   : Blowfish
            !   : not encrypted
         - Messages can be sended using any mode with prefixes:
            +p  : not encrypted
            +a  : AES256CBC
            +b  : Blowfish

COMMANDS:
    /key <nick|#channel> [<--network> <network>] [new_key] : show information or set key
    /key_exchange <nick> : exchange a new key via dh1080
    /key_list : list keys
    /key_load : load keys from internal file
    /key_pass <password> : set key file pass
    /key_remove <nick|#channel> : remove key
    /aes #channel/nick [1|0] or [True|False] : set/unset AES256CBC mode (default AES mode)