Fix source data URL (#4)

- Fix data URL to use HTTPS (94167630704fb66d3bcc432955f4bb8b31bfc225)
- Delete legacy dataset_infos.json (93de2237c7b00a2172a495a6ef42c528630d20bb)

dataset_infos.json

@@ -1 +0,0 @@
-{"sentiment140": {"description": "Sentiment140 consists of Twitter messages with emoticons, which are used as noisy labels for\nsentiment classification. For more detailed information please refer to the paper.\n", "citation": "@article{go2009twitter,\n  title={Twitter sentiment classification using distant supervision},\n  author={Go, Alec and Bhayani, Richa and Huang, Lei},\n  journal={CS224N project report, Stanford},\n  volume={1},\n  number={12},\n  pages={2009},\n  year={2009}\n}\n", "homepage": "http://help.sentiment140.com/home", "license": "", "features": {"text": {"dtype": "string", "id": null, "_type": "Value"}, "date": {"dtype": "string", "id": null, "_type": "Value"}, "user": {"dtype": "string", "id": null, "_type": "Value"}, "sentiment": {"dtype": "int32", "id": null, "_type": "Value"}, "query": {"dtype": "string", "id": null, "_type": "Value"}}, "supervised_keys": null, "builder_name": "sentiment140", "config_name": "sentiment140", "version": {"version_str": "1.0.0", "description": "", "datasets_version_to_prepare": null, "major": 1, "minor": 0, "patch": 0}, "splits": {"test": {"name": "test", "num_bytes": 73365, "num_examples": 498, "dataset_name": "sentiment140"}, "train": {"name": "train", "num_bytes": 225742946, "num_examples": 1600000, "dataset_name": "sentiment140"}}, "download_checksums": {"http://cs.stanford.edu/people/alecmgo/trainingandtestdata.zip": {"num_bytes": 81363704, "checksum": "004a3772c8a7ff9bbfeb875880f47f0679d93fc63e5cf9cff72d54a8a6162e57"}}, "download_size": 81363704, "dataset_size": 225816311, "size_in_bytes": 307180015}}

sentiment140.py

@@ -21,7 +21,7 @@ Sentiment140 consists of Twitter messages with emoticons, which are used as nois
 sentiment classification. For more detailed information please refer to the paper.
 """
 _URL = "http://help.sentiment140.com/home"
-_DATA_URL = "http://cs.stanford.edu/people/alecmgo/trainingandtestdata.zip"
+_DATA_URL = "https://cs.stanford.edu/people/alecmgo/trainingandtestdata.zip"
 
 _TEST_FILE_NAME = "testdata.manual.2009.06.14.csv"
 _TRAIN_FILE_NAME = "training.1600000.processed.noemoticon.csv"