Changes

New Stuff

Subcommands
- Since groups can't be executed on their own, their coroutines are used as checks instead.
- Command.parent references its parent group
- Command.qualname gives the fully qualified name
- class Group: @.slash_cmd(), @.slash_group()
- @SlashBot.slash_group(), @slash.group()
Context.options is a dict of option names to values that will be passed/have been passed to the command coroutine
logging.getLogger('discord.ext.status')
@Command.check registers a command-specific check
check is also a new kwarg in Command.__init__
Choice.from_data supports string values (which are doubled) and dict values (which are **ed) and Choice values (which are passed through)
Option.choices has Choice.from_data mapped onto it
demo_bot.py is an example of how to use the library

Command.method renamed to Command.coro
Slash commands will only start being dispatched once the ready event is triggered the first time
The CommandNotFound error is directly raised instead of dispatched through the event system
Interaction objects are now only supported at version 1.

Some ext.commands things broke because Command.cog didn't exist. It does now, and is always None
When Context.guild is a discord.Object, that used to cause the member fetching to fail because of an AttributeError
allowed_mentions was being ignored in respond if SlashBot.allowed_mentions was None
Reusing the same Option instance used to set the name of all options that use it to be the same. Now the instance is cloned instead.
Options with choices used to be broken because Option.to_dict didn't call Choice.to_dict