[GH-15] Fixed double hyphen handling

[UrsaDK]

• Fixed double hyphen handling within short options
• Added more tests to cover Double hyphen not handled correctly in some situations #15
• Updated documentation
• Test suit improvements

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (f266f21) to head (50b4987).
Report is 1 commits behind head on master.

Additional details and impacted files