Create initial solution structure
Add `Horse` information class
Configure project settings and add comments.

Enable warnings as errors and numeric under/overflow detection.
Link the test project to the library.
Strongly sign both projects.
Add comments to all public classes and members.
Add `OfficialAge` and `Gender` properties to `Horse` class.
Create `Gender` enum type.
Enable code analysis on library project.
Calculate `Horse`'s actual age.
Add official age calculation, exception tests, and Unknown Gender option
Merge with GitHub repository files