Training improvements

[n1t0]

This issue is here to keep track of the different subjects around training.

• [x] Ability to train from memory (#198)
• [ ] Ability to re-train a Tokenizer with relevant parameters (#525)
• [x] Extract the word-counts to each Trainer (#524)
• [ ] AddedVocabulary does not play well with the Model (#523)
• [x] Trainer trains the Model in-place (#526)
• [x] Make the trainer optional when training (#527)

[github-actions[bot]]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days.