Release minor fixes

[Roman223]

Have done:

1. Не обновляются типы узлов при передаче в set_structure пустого списка рёбер #65
2. Возможно, вот эту часть стоит переработать в виде Factory. #53

List of oncomings:

• Serialization problem Regressors serialization  #48

[pep8speaks]

Hello @Roman223! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file bamt/networks/base.py:

Line 330:17: W503 line break before binary operator
Line 336:17: W503 line break before binary operator
Line 468:17: W503 line break before binary operator
Line 469:17: W503 line break before binary operator
Line 470:17: W503 line break before binary operator
Line 543:17: W503 line break before binary operator
Line 544:17: W503 line break before binary operator
Line 545:17: W503 line break before binary operator

• In the file bamt/networks/big_brave_bn.py:

Line 32:21: W503 line break before binary operator