Feature/delete multiple images 77123524

[finishes: #77123524]
[finishes: #78768594]

Allows users to multi select images but removes the checkbox option for panamax images.

optionally, I think you could just do something like  this:
```
var checked = $target.is(':checked');
base.$el.find(base.options.deleteCheckbox).prop('checked', checked);
```