[issue-2] Allow users to select the prime number verification algorithm

[ddcprg]

Fixes #2

[coveralls]

Pull Request Test Coverage Report for Build 9

• 26 of 26 (100.0%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+2.9%) to 91.549%

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Totals
Change from base Build 7:	2.9%
Covered Lines:	65
Relevant Lines:	71

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💛 - Coveralls