Release 0.1.5.6

New features:

• Plugins can listen for events. (feat: events, plugin can listen now)
• Error handling. (feat: error handling)
  Now, you can make yours error handling by overriding client and their on_command_error method.

Optimization and safety:

• For some classes, __slots__ has been fixed.
• PluginManager bot, client, commands attributes now are private. (chore(PluginManager): convert bot, client, commands attributes …)
• Commands being get by ID from now. (chore: now commands locating by ID)

Fixed:

• Option description attribute was required, but now is optional.
• For some classes, __slots__ has been fixed.
• In SlashCommand examples was problem with tabs.
• Package __version__ and __version_tuple__ are now is uneditable.

* psss, bug hunting is very welcome, as suggestions and reviews!