Paintings in structure blocks not loading in same place

The bug

When you place a painting in a Structure and save it using the Save Structure Block, and then Load the structure, the painting will sometimes load one block off.

• All paintings with even height are loaded off in +Y axis
• A painting with even width is off if
  • it looks towards +Z when loaded, then it's loaded off in +X
  • it looks towards -X when loaded, then it's loaded off in +Z

Affects rotating/mirroring

Cause

The problem seems to be that the Pos tag of hanging entities refers to the center of the entity, however when it is created the passed position is the position of its corner. This could probably be solved by using the TileX, TileY and TileZ values for hanging entities.