Update tweet.py

twint/tweet.py

 class Tweet:
     id = ""
-	date = ""
+    datetime = ""
     datestamp = ""
-	time = ""
     timestamp = ""
     timezone = ""
     user_id = ""
     username = ""
-	tweet = "" # Text
+    tweet = ""
     replies = "0"
     likes = "0"
     retweets = "0"
     hashtags = ""
     location = ""
     link = ""
+    is_retweet = False
+    user_rt = "" # User that retweeted