Split models.py into several files (#398)

* Move exception models into separate file
* Move thread model into separate file
* Move user model into separate file
* Move group and room models into separate file
* Move page model into separate file
* Move message model into separate file
* Move basic attachment models into separate file
* Move sticker model into separate file
* Move location models into separate file
* Move file attachment models into separate file
* Move mention model to reside with message model
* Move quick reply models into separate file
* Move poll models into separate file
* Move plan model into separate file
* Move active status model to reside with user model
* Move core enum model into separate file
* Move thread-related enums to reside with thread model
* Move typingstatus model to reside with user model
* Move emojisize and reaction enums to reside wtih message model

fbchat/_group.py

@@ -0,0 +1,67 @@
+# -*- coding: UTF-8 -*-
+from __future__ import unicode_literals
+
+from ._thread import ThreadType, Thread
+
+
+class Group(Thread):
+    #: Unique list (set) of the group thread's participant user IDs
+    participants = None
+    #: A dict, containing user nicknames mapped to their IDs
+    nicknames = None
+    #: A :class:`ThreadColor`. The groups's message color
+    color = None
+    #: The groups's default emoji
+    emoji = None
+    # Set containing user IDs of thread admins
+    admins = None
+    # True if users need approval to join
+    approval_mode = None
+    # Set containing user IDs requesting to join
+    approval_requests = None
+    # Link for joining group
+    join_link = None
+
+    def __init__(
+        self,
+        uid,
+        participants=None,
+        nicknames=None,
+        color=None,
+        emoji=None,
+        admins=None,
+        approval_mode=None,
+        approval_requests=None,
+        join_link=None,
+        privacy_mode=None,
+        **kwargs
+    ):
+        """Represents a Facebook group. Inherits `Thread`"""
+        super(Group, self).__init__(ThreadType.GROUP, uid, **kwargs)
+        if participants is None:
+            participants = set()
+        self.participants = participants
+        if nicknames is None:
+            nicknames = []
+        self.nicknames = nicknames
+        self.color = color
+        self.emoji = emoji
+        if admins is None:
+            admins = set()
+        self.admins = admins
+        self.approval_mode = approval_mode
+        if approval_requests is None:
+            approval_requests = set()
+        self.approval_requests = approval_requests
+        self.join_link = join_link
+
+
+class Room(Group):
+    # True is room is not discoverable
+    privacy_mode = None
+
+    def __init__(self, uid, privacy_mode=None, **kwargs):
+        """Deprecated. Use :class:`Group` instead"""
+        super(Room, self).__init__(uid, **kwargs)
+        self.type = ThreadType.ROOM
+        self.privacy_mode = privacy_mode