re-release of feature branch for requirements update

downgrade scipy for tensorflow, upgrade pillow for security warning

upgrade spacy tensorflow pandas and scikit

Upgrade nltk, spacy, tensorflow, keras, gensim

Update anki api for new license column. Update regex tests to deal wi…

…th new regex class repr

Pinned plotly version and fix pytest tests. tests_require = annoy; me…

…chanicalsoup;

add spyder to readme

Pin levenshtein requirement in requirements.txt so that it doesn't fa…

…il to install with pip after successful install with conda. SEE [comment 494687 by Dan Parvaz on LiveBook](https://livebook.manning.com/book/natural-language-processing-in-action/chapter-2/comment-494687)

Standardize KeyedVectors import, gensim version, and remove cufflinks…

… requirement.

Remove annoy dependency. Updated regex doctests. Update nltk dependen…

…cy for security vulnerability. Thank you for your testing Bob Liu, livebook.manning.com reader, Sept 12, 2019.