Add support for reactions.

Reactions can be be standard emojis, or custom server emojis.

Adds
 - add/remove_reaction
 - get_reaction_users
 - Messages have new field reactions
 - new events - message_reaction_add, message_reaction_remove
 - new permission - add_reactions

discord/reaction.py

@@ -0,0 +1,88 @@
+# -*- coding: utf-8 -*-
+
+"""
+The MIT License (MIT)
+
+Copyright (c) 2015-2016 Rapptz
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+"""
+
+from .emoji import Emoji
+
+class Reaction:
+    """Represents a reaction to a message.
+
+    Depending on the way this object was created, some of the attributes can
+    have a value of ``None``.
+
+    Similar to members, the same reaction to a different message are equal.
+
+    Supported Operations:
+
+    +-----------+-------------------------------------------+
+    | Operation |               Description                 |
+    +===========+===========================================+
+    | x == y    | Checks if two reactions are the same.     |
+    +-----------+-------------------------------------------+
+    | x != y    | Checks if two reactions are not the same. |
+    +-----------+-------------------------------------------+
+    | hash(x)   | Return the emoji's hash.                  |
+    +-----------+-------------------------------------------+
+
+    Attributes
+    -----------
+    emoji : :class:`Emoji` or str
+        The reaction emoji. May be a custom emoji, or a unicode emoji.
+    custom_emoji : bool
+        If this is a custom emoji.
+    count : int
+        Number of times this reaction was made
+    me : bool
+        If the user has send this reaction.
+    message: :class:`Message`
+        Message this reaction is for.
+    """
+    __slots__ = ['message', 'count', 'emoji', 'me', 'custom_emoji']
+
+    def __init__(self, **kwargs):
+        self.message = kwargs.pop('message')
+        self._from_data(kwargs)
+
+    def _from_data(self, reaction):
+        self.count = reaction.get('count', 1)
+        self.me = reaction.get('me')
+        emoji = reaction['emoji']
+        if emoji['id']:
+            self.custom_emoji = True
+            self.emoji = Emoji(server=None, id=emoji['id'], name=emoji['name'])
+        else:
+            self.custom_emoji = False
+            self.emoji = emoji['name']
+
+    def __eq__(self, other):
+        return isinstance(other, self.__class__) and other.emoji == self.emoji
+
+    def __ne__(self, other):
+        if isinstance(other, self.__class__):
+            return other.emoji != self.emoji
+        return True
+
+    def __hash__(self):
+        return hash(self.emoji)