Use fromRawAttributes() for custom pivot models

[mjauvin]

Fixes wintercms/winter#741

[mjauvin]

@hirisov if you could test this fix, that would be appreciated.

Thanks.

[mjauvin]

@bennothommo this should resolve the issue with the User's Roles awards in Winter.Test plugin as well.

[LukeTowers]

@mjauvin does line 838 also need to be changed?

[mjauvin]

@mjauvin does line 838 also need to be changed?

I don't think so, but I'm not 100% sure.

[mjauvin]

@mjauvin does line 838 also need to be changed?

According to the newPivot() method in Laravel's Eloquent Model, I think we're good:

    public function newPivot(self $parent, array $attributes, $table, $exists, $using = null)
    {   
        return $using ? $using::fromRawAttributes($parent, $attributes, $table, $exists)
            : Pivot::fromAttributes($parent, $attributes, $table, $exists);
    }       

But I realize we could completely remove our overriden method now, since it's a carbon copy of Laravel's ...

[mjauvin]

See #185

[LukeTowers]

See #185 (comment), our override is necessary to return our version of the Pivot model.