Topicnet

* Reworked top_tokens_viewer and top_documnets_viewer
* Added WNTM recipe
* Added dataset_cooc
* Reworked dataset
* Speed up get_possible_modalities
* Reworked write_vw
* Added new regularizer thetaless and demo of its usage and benefits

Various changes, as can be seen in release commit [description](https://github.com/machine-intelligence-laboratory/TopicNet/pull/43)

Fixed

Recipes `topicnet.cooking_machine.recipes` now included in the assembly on PyPi: setup.py updated, project rebuilt and uploaded.

New

* Added demo notebooks:
* [one](https://github.com/machine-intelligence-laboratory/TopicNet/blob/master/topicnet/demos/20NG-GenSim%20vs%20TopicNet.ipynb): some comparison of TopicNet with Gensim library
* [two](https://github.com/machine-intelligence-laboratory/TopicNet/blob/master/topicnet/demos/Making-Decorrelation-and-Topic-Selection-Friends.ipynb): example of analysis of the 20 Newsgroups dataset, more examples of how one can conduct topic modeling with the help of TopicNet and ARTM
* [three](https://github.com/machine-intelligence-laboratory/TopicNet/blob/master/topicnet/demos/20NG-PREPROCESSING.ipynb): more about 20 Newsgroups dataset analysis before actual topic modeling

Fixed

* Improved top tokens html display by TopTokensViewer
* Fixed TopicNet installation via pip: now all the necessary packages should be installed automatically.
So the command `pip install topicnet` should work just fine... for Linux :)

Future Plans

* Add new regularizers
* Add more abilities to control TopicModel's training process — with `model.fit()` function
* Make the library installable with `pip` also for Windows and Mac without BigARTM preinstalled

* Enable end-to-end `pip install topicnet` (without BigARTM preinstalled) for Linux users.

* Adding recipe import into the library

* Support of custom regularizers

* Experimental feature allowing to change regularization coefficients during model training

* Documentation updated

* Various code improvements

Recipe demo-notebook and minor changes in cubes added.