[3.0] Added Custom Makers Per Definition

In Factory Muffin 3.0, the ability to register custom makers/setters/deleters on the factory muffin class has been removed because it was quite poorly designed, and the model definition registration has been improved massively fixing a few design problems we had before, and improving the definition group functionality.

I now propose that we allow people to register custom makers during this definition registration process, so in the same way you can define attribute definitions and callback for your models, you will also be able to register a custom maker closure.


Ok, so what does this mean for my code then?

Factory Muffin 2.1:
```php
FactoryMuffin::define('Foo', []);
FactoryMuffin::define('extra:Foo', ['user' => 'firstNameMale']);
FactoryMuffin::define('Bar', []);
FactoryMuffin::define('Baz', []);

// no way to handle makers custom to groups
// we have to do this all at once - not very flexible
FactoryMuffin::setCustomMaker(function($class) {
    if ($class === 'Foo') {
        return new $class('bar');
    } elseif ($class === 'Bar') {
        return new $class('baz');
    } else {
        return new $class();
    }
});
```

Factory Muffin 3.0:
```php
$fm = new FactoryMuffin();

$fm->define('Foo')
    ->setMaker(function ($class) {
        return new $class('bar');
});

$fm->define('extra:Foo')
    ->addDefinition('user', Faker::firstNameMale())
    ->setMaker(function ($class) {
        return new $class('hello');
});

$fm->define('Bar')
    ->setMaker(function ($class) {
        return new $class('baz');
});

$fm->define('Baz');
```