This adds:
* CategoryChannel, which represents a category
* Guild.by_category() which traverses the channels grouping by category
* Guild.categories to get a list of categories
* abc.GuildChannel.category to get the category a channel belongs to
* sync_permissions keyword argument to abc.GuildChannel.edit to sync
permissions with a pre-existing or new category
* category keyword argument to abc.GuildChannel.edit to move a channel
to a category
This adds a new enum named VerificationLevel to denote said verification
level. This enum will also be used in the Client.edit_server calls
instead of the undocumented int parameter.
When clicking on an invite link without having a Discord account it's
possible to create an unclaimed account for joining the conversation
quickly. Add register() method to Client that performs and invite based
registration of an unclaimed account.
Mippy (William)
Rapptz
Gorialis
Khazhismel Kumykov
Hornwitser