BulkMessageDelete Exception

User.Edit(nickname: "foo");

Added SelfBot Functionality by Config

`Message.MentionedRoles` is now populated properly with roles.
`Role.IsMentionable` has been added to determine whether
`Role.Mention` now mentions roles that are `IsMentionable` as expected (otherwise returns empty string)
`Role.Edit` now takes parameter `bool? isMentionable`
`Server.CreateRole` now takes parameter `bool isMentionable`
`IsMentionable` added to `UpdateRoleRequest`

A few users requested an IsBot field for marking Bot Accounts;

Bumping Version number because it has been 0.9-rc3 forever and that's caused a bit of confusion in the channel with what version users are on.