Fix access to $crud in button from model function
Fix access to $crud in button from model function

If stack is 'line' and button type is 'model_function' you don't have access to the `$crud` object.

I think it's wrong anyway because we're calling the same method with two different parameter types: 
line 5 `$entry->{$button->content}($entry)`  <-- here we won't have `$crud` available to the method; instead `$entry` is unnecessarily passed as parameter, it will be available implicitly as `$this`
and
line 7 `$crud->model->{$button->content}($crud)`
Laravel-Backpack/crud,Laravel-Backpack/crud,Laravel-Backpack/crud,Laravel-Backpack/crud