Blender Git Loki

Fix rest of #27022, collada export: add bone parenting of objects

- SceneExporter collects a list of child-objects for armature-object and passes it onto ArmatureExporter
- SceneExporter's writeNodes is then called from ArmatureExporter for matching child-objects for bone.
- ArmatureExporter removes written child-objects from list, objects not exported as being bone parented are exported as direct children of the armature-node.
- Should play nice with current Second Life-compatibility.

A nicer implementation would require some design changes, will have to wait.