Disabled languages still accessible

[alexiswbr]

When you set the active value to false for a language, this language still appear when you edit the translations files. I think it is because of this line :

// Backpack\LangFileManager\app\Http\Controllers\LanguageCrudController
$this->data['languages'] = $languages->orderBy('name')->get();

// fixed with

this->data['languages'] = $languages->orderBy('name')->where('active', 1)->get();

I made a pull request, don't really know how to assign it to this issue

[lloy0076]

https://laravel-backpack.readme.io/docs/crud-fields#section-range

[lloy0076]

Closing - was merged in #33.