Expose Metadata

Added access to:
* `/users/@me/guilds`
* `/guilds/{guild_id}`
* `/guilds/{guild_id}/members/{member_id}`

BREAKING CHANGE:
* `get_user_info` -> `fetch_user_info` to match naming scheme.

Remove useless note

Remove `reverse` and corresponding documentation

Update documentation to reflect #1988

Rename `get_` HTTP functions to `fetch_`

Breaking Changes:
* `get_message` -> `fetch_message`
* `get_invite` -> `fetch_invite`
* `get_user_profile` -> `fetch_user_profile`
* `get_webhook_info` -> `fetch_webhook`
* `get_ban` -> `fetch_ban`

Fix InviteConverter, update migrating.rst

Rename get_message to fetch_message

discord/abc.py

@@ -816,7 +816,7 @@ class Messageable(metaclass=abc.ABCMeta):
         """
         return Typing(self)
 
-    async def get_message(self, id):
+    async def fetch_message(self, id):
         """|coro|
 
         Retrieves a single :class:`.Message` from the destination.