[docs] Custom actions

[ozodrukh]

Hi, i make 2 custom actions dropdown and up, but i'm need only two lines (for library 3 is necessary)
with it my action animation is ugly, also please understand LineSegments

public class DropdownAction extends Action{

    public DropdownAction() {

        lineData = new float[]{
                // first line
                0.2f, 0.7f, 0.5f, 0.4f,
                // second line
                0.45f, 0.4f, 0.75f, 0.7f,
                // third line @unused
                0,0,0,0
        };

    }

}


public class UpAction extends Action{

    public UpAction() {

        lineData = new float[]{
                // first line
                0.2f, 0.4f, 0.5f, 0.7f,
                // second line
                0.45f, 0.7f, 0.75f, 0.4f,

                0,0,0,0
        };
    }
}