[Opt 2.0] Finished the last chapter in the docs.
[Opt 2.0] New method: Opt_View::clear().
[Opt 2.0] New unit tests.
[Opt 2.0] Improved integration of opt:show and snippets.
[Opt 2.0] Improved support for basicOOP option.
[Opt 2.0] Fixed handling of empty expressions.
[Opt 2.0] OPT Version changed to 2.0.0. Preparing for the final release.