Support for max_features

[a-n-ermakov]

26 implementation

Backward compatible with previous version

[coveralls]

Pull Request Test Coverage Report for Build 85

• 55 of 55 (100.0%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 97.642%

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Totals
Change from base Build 79:	0.3%
Covered Lines:	414
Relevant Lines:	424

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💛 - Coveralls

[a-n-ermakov]

According to this stackoverflow question, travis CI has a limit for log of 4MB

https://stackoverflow.com/questions/30463993/is-there-a-limitation-on-the-log-lines-in-a-travis-build