added support for loading .off files: works but the simplification algorithm...

added support for loading .off files: works but the simplification algorithm seems to break "real-world" objects from ModelNet40 with non-uniform triangle density, e.g. in chair_0451 the overall chair shape disappears, keeping only the seat and its nearby parts connecting it to (now non-existent) legs, so that it looks more like a table; when "simplifying less" (targeting more faces/triangles than 1024, about 7000), the backrest is there but legs are partially missing