Download error on scene_parse_150
Hi! The server with the data seems to be down. I've reported this issue (https://github.com/CSAILVision/sceneparsing/issues/34) in the dataset repo.  The URL seems to work now, and therefore the script as well.
```
from datasets import load_dataset
dataset = load_dataset("scene_parse_150", "scene_parsing")

FileNotFoundError: Couldn't find file at http://data.csail.mit.edu/places/ADEchallenge/ADEChallengeData2016.zip
```
