Move all the raw tweets for tests into their own JSON files

Seems better to have the raw data as JSON, like it comes from the API,
then load it into python objects for each test.

tests/tweets/reply.json

@@ -0,0 +1,62 @@
+{
+  "display_text_range":[
+    12,
+    114
+  ],
+  "in_reply_to_status_id_str":"742374355531923456",
+  "source":"<a href=\"http://twitter.com\" rel=\"nofollow\">Twitter Web Client</a>",
+  "geo":null,
+  "full_text":"@philgyford Here\u2019s a test tweet that goes on as much as possible and includes an image. Hi to my fans in testland! https://t.co/tzhyk2QWSr",
+  "extended_entities":{
+    "media":[
+
+    ]
+  },
+  "id_str":"300",
+  "in_reply_to_status_id":742374355531923456,
+  "id":300,
+  "in_reply_to_screen_name":"philgyford",
+  "retweet_count":0,
+  "user":{
+
+  },
+  "created_at":"Mon Jun 13 15:48:06 +0000 2016",
+  "lang":"en",
+  "favorite_count":0,
+  "coordinates":null,
+  "place":null,
+  "contributors":null,
+  "in_reply_to_user_id":12552,
+  "in_reply_to_user_id_str":"12552",
+  "retweeted":false,
+  "favorited":false,
+  "truncated":false,
+  "entities":{
+    "user_mentions":[
+      {
+        "id_str":"12552",
+        "id":12552,
+        "screen_name":"philgyford",
+        "name":"Phil Gyford",
+        "indices":[
+          0,
+          11
+        ]
+      }
+    ],
+    "media":[
+
+    ],
+    "hashtags":[
+
+    ],
+    "symbols":[
+
+    ],
+    "urls":[
+
+    ]
+  },
+  "is_quote_status":false,
+  "possibly_sensitive":false
+}