Consolidate and update

leenkx/Sources/iron/Scene.hx

@@ -1003,7 +1003,7 @@ class Scene {
 			}
 
 			if (o.vertex_groups != null) {
-				cast(object, MeshObject).vertexGroups = new Map();
+				object.vertexGroups = new Map();
 				for (p in o.vertex_groups) {
 					var verts:Array<iron.math.Vec4> = [];
 					
@@ -1014,7 +1014,7 @@ class Scene {
 							verts.push(new iron.math.Vec4(data[i * 3], data[i * 3 + 1], data[i * 3 + 2], 1.0));
 						}
 					}
-					cast(object, MeshObject).vertexGroups.set(p.name, verts);
+					object.vertexGroups.set(p.name, verts);
 				}
 			}