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.
With a bit of help of `indent -linux`, but mostly by hand. Also used
`iconv -f ISO-8859-1 -t UTF-8//TRANSLIT` to convert to UTF-8.
There is still some refactoring left to do.
