Add a lookup for alternatives on CNF - Did you mean one of this?

This will add a lookup for alternatives if a command or an action is not found.
![cnf-lookup](https://f.cloud.github.com/assets/33978/1646707/9ea4a67c-5924-11e3-9cc3-b2c097096fda.png)
![cnf-lookup1](https://f.cloud.github.com/assets/33978/1646708/9eb877a6-5924-11e3-96e9-82cc4cc0db59.png)

Note: This has been inspired by https://github.com/joomla/joomla-framework/pull/275 and https://github.com/symfony/symfony/blob/db4f5515272874eac36fb46a9d45737c2a1319ef/src/Symfony/Component/Console/Application.php#L1048-1089