The previous code relied too much on assertions, even for things that
are just regular things that may happen while the application is running
(like running out of memory).
- Many assertions have been turned into permanent checks
- Some functions now return "success" or "failure".
- NE_Init3D() and NE_InitDual3D() (and others) have been reworked to
handle failures gracefully.
Rendering NEA files has a terrible performance. Instead of trying to
support both formats, remove NEA and replace it by DSMA.
Some function signatures have changed to adapt to the new system.
"NE_ANIM_UPDOWN" has been removed because it's redundant: Just modify
the animation before exporting it from Blender.