void ReadHierarchy(XmlElement element, SpriterHierarchy hierarchy)
{
foreach(XmlElement child in element)
{
// bone
if (child.Name.Equals("bone"))
{
ReadBone(hierarchy, child);
}
// bone_ref
else if (child.Name.Equals("bone_ref"))
{
ReadBoneRef(hierarchy, child);
}
}
}