optimization: move rare propery field to extra structure to minimize memory footprint...

optimization: move rare propery field to extra structure to minimize memory footprint of LOTTransformData.

- only layer transform object can have position property as separate X and Y
  by keeping them in the main structure incurs an overhead of 32 bytes to the user of the structure.
  as well as 8 byte on the book keeping (mSeparate) by moving those rarely used field along with 3D
  data to ExtraData we could trim the object size by 40bytes.

- with this patch now the object size is reduced from 128 bytes to 88bytes.