Refactor the project to be used as a library only.

The allows for a leaner project with fewer dependencies.

The CLI app will be split into a separate project, https://github.com/wsdl2phpgenerator/wsdl2phpgenerator-cli.

- Remove CLI files
- Remove symfony/console and psr/log dependencies
- Remove and ignore composer.lock
- Adjust travis to only test for symfony/options-resolver
Keep the LoggerInterface from psr/log.

The interface defines how the project can perform logging.
Merge branch 'vakopian-remove-cli' into 3.x