EMI: Fix attach and detach (again)

This change set is still incomplete, but I'd like some feedback! The actor's position is calculated incorrectly still, but the rest seem to be correct. I don't think the testing patch can be merged.

Currently, the actor's position, world position and rotation are incorrect. This problem isn't obvious because most of the situations where there is attaching and detaching, there is only one actor or one of the actors has a trivial case (such as 0,0,0 for rotation). This fixes the rotation and detaching, but the position is still wrong.
Why inverse? If the transposing and inversing is needed for correct rendering, the real problem could be somewhere else. For example the memory layout of our matrices is the transpose of what OpenGL expects, so matrices need to be transposed before they are passed to OpenGL. That should happen in the renderer, not in game code though.