Remove CLI related files. Fixes #117

This goes together with https://github.com/wsdl2phpgenerator/wsdl2phpgenerator-cli/pull/1
Based on my tests there is no reason to remove references to `Psr\Log\LoggerInterface`. 

As long as the calling code does not access the logger the code is never evaluated and a `ClassNotFoundException` is never thrown. This is partially due to the fact that we do not use a [`NullLogger`](https://github.com/php-fig/log/blob/master/Psr/Log/NullLogger.php) and instead check whether `$logger` property is set.

I would like to keep the references in place for stronger typing even though we no longer need `psr/log` as a dependency.