Fire event on theme change
Fire event on theme change

The event `igaster.laravel-theme.change` will now be fired when the theme is changed. The payload will be the `Theme`.

This can be used as below:

```php
\Event::listen('igaster.laravel-theme.change', function (Theme $theme = null) {
    if(!is_null($theme) && $theme->name === 'my-theme-name'){
        \Log::info('theme was changed to our theme ');
    } elseif(is_null($theme)){
        \Log::info('theme was changed to one that doesn't exist');
    }
});
```
igaster/laravel-theme