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**Added**
- nbrmd will always open notebooks, even if header of code cells are not terminated. Merge conflicts can thus be solved in Jupyter directly.
- New metadata 'main language' that preserves the notebook language.
**Fixed**
- dependencies included in `setup.py`
- pre_save_hook work with non-empty `notebook_dir` ([9](https://github.com/mwouts/jupytext/issues/9))