2.3
 - New options '--include-archives', '--exclude-archives',
   '--include-codenames', --exclude-codenames'.
 - New option '--show-not-preferred'.
 - The action summary is now shown by default in the action preview.
   New related options '--summary-only', '--no-summary'.
 - 'search' now searches in localized descriptions if they are available.
 - Metadata updater doesn't attempt to download unexisting index localizations
   anymore.
 - Multiple index localizations are now supported (using the option
   'cupt::languages::indexes').
 - The action preview can be colored now (using the option
   'cupt::console::use-colors').

2.2
 - New positional action override options '--install', '--remove', '--purge',
   '--satisfy', '--unsatisfy'.
 - The quality of generating dpkg package sequence is improved; it's also much
   faster now.
 - Implemented logging.
 - Added an initial support of repository index deltas (PDiffs).

2.1
 - New subcommand 'showauto'.
 - Implemented regular expressions in pin preferences.
 - Now uses its own directory for package metadata.

2.0
 - Re-implemented in C++(0x).
 - A tutorial is now available.
 - Added a support for multiple upstream tarballs in source packages.
 - More descriptive error messages for errors in configuration files.
 - Implemented refusing expired Release files.
 - New wget-based download method for http(s)/ftp.
 - Implemented dpkg action priority heuristics to reduce the time from the
   package state is changed till the package state is final.
 - New configurable score calculation system in the native resolver
   (new option group 'cupt::resolver::score::*').
 - When no solutions were found, throw an error with a solution tree(s) to
   show why.
 - Automatically determine packages which need an indirect upgrade, making the
   option 'cupt::worker::allow-indirect-upgrade' unneeded.
 - Added an ability to specify additional package expressions and restart the
   solving process in the action preview prompt (new choice 'a').
 - Don't use randomization anymore for implementing
   'cupt::worker::archives-space-limit' option. Deleted option
   'cupt::worker::archives-space-limit::tries'.
