* Trainer - deprecate tokenizer for processing_class
* Extend chage across Seq2Seq trainer and docs
* Add tests
* Update to FutureWarning and add deprecation version
* torchscript and trainer md es translation
* corrected md es files and even corrected spelling in en md
* made es corrections to trainer.md
* deleted entrenamiento... title on yml
* placed entrenamiento in right place