Blender Git Loki

Made plane track transformable by generic transform operators

Pretty much straightforward change, apart form one trick needed
to preserve point tracks scaling nice:

- If TransData belong to point track, use it's individual center
when scaling (ignoring pivot point center).

This works much better for adjusting sizes of point tracks.

- If TransData belongs to plane track, use pivot point settings.

This is done via TransData's flag TD_INDIVIDUAL_SCALE which is
currently used by point tracks conversion code, but might be
used by other transform elements as well.