* Make IDefaultDict a subclass of OrderedDict, so the order of keys is
  remembered.
* Release version 1.7.2.

* Don't generate an exception when comparing an IStr object with an object
  which is not an instance of str.
* Release version 1.7.1.

Add channels parameter, a list of channels the user was in, to on_quit().
Fix an issue where IRCBot.nicklist wouldn't update properly.
Release version 1.7.0.

Fix issue where part messages would always be set to None.
Release version 1.6.2.

Fix issue where IRCBot.nickname wouldn't update after changing nicknames.
Release version 1.6.1.

* Rename IrcBot to IRCBot.
* Replace target parameter with channel in on_message() and on_notice().
* Remove is_self parameter from events.
* Add message parameter to on_kick().
* Remove is_alive().
* Change send_raw() parameters to an IRC command and a list of arguments to the
  command.
* Rename on_other() to on_raw().
* on_raw() is now called for every IRC message, not just ones without a
  specific event.
* Remove async_events parameter from listen() and listen_async().

* Add IStr, a case-insensitive string class.
* Add IDefaultDict, a case-insensitive dictionary class.
* Make all nickname, channel, and target parameters in events case-insensitive.
  See IStr for more information.
* Add IRCBot.nicklist, a case-insensitive dictionary which stores lists of
  users in channels.
* Make IRCBot.channels case-insensitive.
* Make IRCBot.nickname case-insensitive.
* Add a timeout parameter to wait().
* Add a realname parameter to register().
* When given a list of CA certificates, make connect() verify the server's
  hostname as well as its certificate.

* Rename some private methods.
* Rename some private buffers.
* Make methods call send_raw() instead of writeline().
* Handle socket errors more gracefully.
* Make parse() a static method.
* Add format(), which formats IRC messages.
* Make register() wait for RPL_WELCOME instead of MODE.