Use Mono in Unity

After asking how to load additional scripts at runtime in [this post][1], the anwser I got pointed to [this][2] page. Now I was wondering how I can use the class on that page in MonoDevelop. Do I have to import something (maybe a dll)? Or is the Mono package built into **Mono**-Develop [1]: http://answers.unity3d.com/questions/803298/allow-extensions-for-game.html [2]: http://docs.go-mono.com/index.aspx?link=N%3AMono.CSharp