Docker image and integration with Sklearn

2.3.0, 2017-07-25

🌟 New features:

• Add Dockerfile for gensim with external wrappers (@parulsethi, #1368)
• Add sklearn wrapper for Word2Vec (@chinmayapancholi13, #1437)
• Add loss function for Word2Vec. Fix #999 (@chinmayapancholi13, #1201)
• Add sklearn wrapper for AuthorTopic model (@chinmayapancholi13, #1403)

👍 Improvements:

• Remove unittest2 (@souravsingh, #1490)
• Add multiple scoring methods for Phrases. Partial fix #1363 (@michaelwsherman, #1464)
• Add WordRank wrapper to Dockerfile (@parulsethi, #1460)
• Add PathLineSentences. Fix #1364 (@michaelwsherman, #1423)
• Add TextDirectoryCorpus and refactor TextCorpus. Fix #1387 (@macks22, #1459)
• Add sparse input support with topn parameter in any2sparse. Fix #1294 (@manneshiva, #1321)
• Add seed and length for sample_text. Partial fix #308 (@vlejd, #1422)
• Add word_ngram parameter to FastText (@fsonntag, #1432)

🔴 Bug fixes:

• Fix fastText loading from .bin file. Fix #1236 (@prakhar2b, #1341)
• Fix paths in WordRank and running gensim version in Dockerfile (@parulsethi, #1503)
• Fix commit version for gensim in Dockerfile (@parulsethi, #1491)
• Fix encoding problems with tests on windows. Fix #1441 (@menshikh-iv, #1469)
• Fix parameters in score_cbow_pair (@jmhessel, #1468)
• Fix parameters in score_sentence_cbow (@jmhessel, #1467)
• Fix TextDirectoryCorpus on windows (@macks22, #1463)
• Fix gensim version in Dockerfile (@parulsethi, #1456)
• Fix WordOccurenceAccumulator on windows. Fix #1441 (@macks22, #1449)
• Fix scipy/numpy requirements (downgrade). Fix #1450 (@menshikh-iv, #1450)

📚 Tutorial and doc improvements:

• Fix links and spaces in quick start guide (@iamsanten, #1500)
• Fix error of ConcatedDoc2Vec in doc2vec-imdb notebook (@robocator, #1377)
• Fix Sphinx warnings. Fix #1192 (@prerna135, #1442)
• Fix typo in LdaModel.diff method (@parulsethi, #1461)
• Add Tensorboard visualization for LDA (@parulsethi, #1396)
• Update old and add new notebook with CoherenceModel (@macks22, #1431)