Text based protocol for admin commands

[loconox]

Hi,

Realized a quick and dirty class to communicate in text mode with the gearman server. Several admin commands are only available this way and the lib doesn't provide support for this. I'm not used to event based programming, do not hesitate to make comments.

See: https://github.com/loconox/react-gearman/blob/feature/text-based-client/src/Protocol/TextConnection.php