Add 'normalgl' extension

Sources/arm/sys/Path.hx

@@ -18,7 +18,7 @@ class Path {
 
 	public static var baseColorExt = ["albedo", "alb", "basecol", "basecolor", "diffuse", "diff", "base", "bc", "d", "color", "col"];
 	public static var opacityExt = ["opac", "opacity", "alpha"];
-	public static var normalMapExt = ["normal", "nor", "n", "nrm"];
+	public static var normalMapExt = ["normal", "nor", "n", "nrm", "normalgl"];
 	public static var occlusionExt = ["ao", "occlusion", "ambientOcclusion", "o", "occ"];
 	public static var roughnessExt = ["roughness", "rough", "r", "rgh"];
 	public static var metallicExt = ["metallic", "metal", "metalness", "m", "met"];