As a bonus this already fixes several bugs caused by the botched texture scaling implementation the original texture manager came with.
System cursors are currently disabled because they rely on functionality that needs to be moved to different classes.
- Slightly improve how softpoly processes portals
- Pass the vertex transform matrix via a command rather than being part of the drawer args
- Improve zbuffer drawers in the software renderer
- Misc model rendering fixes
Now it is no longer necessary to provide specially set up textures for rendering shaded decals, they can use any PNG texture now that contains a proper red channel.
Handling of the alPh chunk has been removed as a result as it in no longer needed.
