Nullable types cannot be null (fix #167)
Improving test code quality
Abstract Classes Should Not Have Public Constructors (closes #164)
Cleaning the code.
Merge pull request #171 from ElemarJR/FixCC0030

Fix cc0030 - Nullables cannot be const (fix #167)
Merge pull request #173 from ElemarJR/AbstractClassesShouldNotHavePublicConstructors

Abstract Classes Should Not Have Public Constructors (closes #164)