Improved the composer package definition

- changed the autoload from files to classmap to really use autoloading (files is not autoloading, it is eagerloading needed for files defining functions rather than classes)
- removed the explicit version in the file, as this causes more harm than good for packages stored in VCS repos: Composer ignores it for branches, and will consider tags as invalid if the explicit version does not match the version generated based on the tag name.
up version, use Ratchetio subclass instead of class_alias for backwards compatibility