Improve json report of coverage selector and comments generated during assertion

[lacinoire]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build 2535

• 35 of 50 (70.0%) changed or added relevant lines in 11 files are covered.
• 16 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.4%) to 81.256%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
dspot/src/main/java/eu/stamp_project/dspot/common/miscellaneous/DSpotUtils.java	5	6	83.33%
dspot/src/main/java/eu/stamp_project/dspot/common/report/output/selector/coverage/json/TestCaseJSON.java	0	5	0.0%
dspot/src/main/java/eu/stamp_project/dspot/common/report/output/selector/coverage/json/TestClassJSON.java	0	9	0.0%

Files with Coverage Reduction	New Missed Lines	%
dspot/src/main/java/eu/stamp_project/dspot/amplifier/SimpleInputAmplDistributor.java	16	75.76%

Totals
Change from base Build 2534:	-0.4%
Covered Lines:	4825
Relevant Lines:	5938

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💛 - Coveralls

[monperrus]

Thanks @lacinoire, LGTM.

@danglotb merge?