* Added in fca846272e to deal with signed adjustments but its just not needed.
* Made better use of `binangle`/`fixedhoriz` class getters and setters than before as well.
This was by far the messiest game, there's two reasons for this.
First, the portal links do not need to be in an actual portal sector, so they cannot be used to detect portal sectors.
Second, the game moves portals in place, so all offsets are (0,0,0) so that not even these can be used for detection.
The only working method is the super-complicated original way to look up portals at run time, just being done at map start.
Having static portal links should reduce the render glitches quite significantly because the renderer knows now which sectors belong to a portal and can use this information to ensure proper processing.
