Trace expm and pow

[coveralls]

Pull Request Test Coverage Report for Build 1022878822

• 102 of 137 (74.45%) changed or added relevant lines in 9 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-24.8%) to 75.177%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/qutip_tensorflow/core/data/dense_tensor.py	40	53	75.47%
src/qutip_tensorflow/core/data/pow.py	0	22	0.0%
<!--	Total:	102	137	74.45%	-->

Totals
Change from base Build 1003986490:	-24.8%
Covered Lines:	106
Relevant Lines:	141

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💛 - Coveralls