Add Xonotic shaders

shaders/xonotic/1.shader_test

shaders/xonotic/10.shader_test

shaders/xonotic/13.shader_test

shaders/xonotic/16.shader_test

shaders/xonotic/19.shader_test

shaders/xonotic/22.shader_test

shaders/xonotic/25.shader_test

shaders/xonotic/28.shader_test

shaders/xonotic/31.shader_test

shaders/xonotic/34.shader_test

shaders/xonotic/37.shader_test

shaders/xonotic/4.shader_test

shaders/xonotic/40.shader_test

shaders/xonotic/43.shader_test

shaders/xonotic/46.shader_test

shaders/xonotic/49.shader_test

shaders/xonotic/52.shader_test

shaders/xonotic/55.shader_test

shaders/xonotic/58.shader_test

shaders/xonotic/61.shader_test