add coverity_scan.

[MFraters]

a follow up from #3

[coveralls]

Pull Request Test Coverage Report for Build 833

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 98.867%

---

Totals
Change from base Build 827:	0.0%
Covered Lines:	2443
Relevant Lines:	2471

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💛 - Coveralls

[codecov-io]

Codecov Report

Merging #149 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #149   +/-   ##
=======================================
  Coverage   97.23%   97.23%           
=======================================
  Files          58       58           
  Lines        3688     3688           
=======================================
  Hits         3586     3586           
  Misses        102      102

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