Rename Command to AbstractCommand

[wpillar]

Our CONTRIBUTING file states that abstract classes MUST be prefixed with Abstract. L5 comes bundled with a bunch of abstract classes that do not conform to this convention.

Suggest we (read: I) rename them accordingly, starting with this one.

[JN-Jones]

Actually that class can be removed as we'll use MyBB/Core/Console/Commands instead (there's already one command). I don't think we need an abstract class for it.

[wpillar]

Fair enough :) What about these ones?:

• MyBB\Core\Events\Event
• MyBB\Core\Http\Controllers\Controller
• MyBB\Core\Http\Controllers\Api\ApiController
• MyBB\Core\Http\Requests\Request

[JN-Jones]

We haven't decided whether or for what we'll use events so I'd keep it for now. The rest is already used afair so should be renamed.

[euantorano]

Yeah, we'll be using events, but I'm not sure if we'll use that class as the base, or the existing base. You can definitely rename it though :)

[wpillar]

Ok, let's merge this one then and I'll rename the rest. If we don't need 'em we can delete 'em later.

[euantorano]

Ok, consider it merged!