Python 3.7 support

Created by: ololobus

Python 3.7 support https://github.com/deepmipt/DeepPavlov/issues/520

Scikit-learn version changed to 0.19.2 in order to address this issue https://github.com/scikit-learn/scikit-learn/issues/11320

pyTelegramBotAPI version changed to the latest to fix test errors, e.g.:

E             File "/Users/alexk/dev/deeppavlov-dev/utils/telegram_utils/telegram_ui.py", line 18, in <module>
E               import telebot
E             File "/Users/alexk/dev/deeppavlov-dev/dp-venv/lib/python3.7/site-packages/telebot/__init__.py", line 1291
E               @util.async()
E                         ^
E           SyntaxError: invalid syntax

Pip install and basic functionality works fine with Python 3.7.0 now. Tests do not crash, but take forever on my laptop to complete and some of them are skipped, though the same is with current master with Python 3.6.6.