add flag to return internal data

[coveralls]

Pull Request Test Coverage Report for Build 113

• 2 of 4 (50.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.1%) to 83.77%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
toppra/algorithm/algorithm.py	2	4	50.0%
<!--	Total:	2	4	50.0%	-->

Totals
Change from base Build 110:	-0.1%
Covered Lines:	1120
Relevant Lines:	1337

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💛 - Coveralls