Named handlers for SDLx::Controller

[kthakore]

What about get names for all handlers? For example:

$app->add_move_handler(player => sub{...});
$app->add_move_handler(unit1 => sub{...});
$app->add_move_handler(unit2 => sub{...});

...

$app->remove_move_handler('unit1');

It`s get more flexible behavior. Not need store indexes and use them, just use name what you set and you known.

To do:

• Replace handlers array to hash
• For save current behavior: set number as key for handler if key not specified

What do you think about that?