Changes in this version:
- Added high detail graphics mode. In this mode sprites are drawn at full resolution and texture mipmapping is removed. There is a modest framerate penalty.
- Various Memory savings. Saved a few kb here and there by using bitfields, factoring out struct members. All of Plutonia with the exception of Map 28 will load and play now on Nightmare.
- Use the original iD Doom Zone memory allocator. This removes some overhead from each memory allocation.
- Minor performance improvements.