- fixed reading meshes without faces.
also changed...
- read verts/faces/uvs in one struct.unpack(), should be a bit faster.
- removed mesh/material splitting, very confusing/slow code and not needed since the 16 material limit was removed.
- load image paths with bpy.path.resolve_ncase() since many 3ds's files has case mismatch with file names (applies to OBJ too).