Added unit tests for stroke-linejoin property
Added unit tests for stroke-linejoin property

AngleSharp/AngleSharp,FlorianRappl/AngleSharp,FlorianRappl/AngleSharp,FlorianRappl/AngleSharp,AngleSharp/AngleSharp,AngleSharp/AngleSharp,AngleSharp/AngleSharp,FlorianRappl/AngleSharp,AngleSharp/AngleSharp