Dev

[davebulaval]

This PR fixes the following:

• Fix and improve documentation.
• Remove fixed dependencies version.
• Fix app errors.
• Add data validation for 1) multiple consecutive whitespace and 2) newline.
• Fixes some errors in tests.
• Add an argument to the DatasetContainer interface to use a pre-processing data cleaning function before validation.
• Hot-fix the issue with the BPEmb base URL download problem. See issue 221.
• Fix the NumPy version due to a major release with breaking changes.
• Fix the SciPy version due to breaking change with Gensim.
• Fix circular import in the API app.
• Fix deprecated max_request_body_size in Sentry.