(Big) transformer Tatoeba models

[PhilLint]

The current version does not support (big) transformer models from the Tatoeba Challenge provided on hugging face (https://huggingface.co/Helsinki-NLP/opus-mt-tc-big-fi-en), right? If not, do you plan to add those? This seems important to overcome strange translation behaviour (e.g. https://github.com/Helsinki-NLP/Opus-MT/issues/55). We encountered similar weird translations including repetitions of certain strings, some weird non related words added and suboptimal language detection especially for asian languages. Thanks!