Update master branch to version 1.9.0

[coveralls]

Pull Request Test Coverage Report for Build 478

• 276 of 283 (97.53%) changed or added relevant lines in 5 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.005%) to 97.564%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pymcmcstat/propagation.py	250	257	97.28%
<!--	Total:	276	283	97.53%	-->

Totals
Change from base Build 428:	-0.005%
Covered Lines:	2603
Relevant Lines:	2668

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💛 - Coveralls