Except not working with for_each and include_sub_dirs

Hi folks,
testing aviator behaviour and going through the code I noticed that the `except` piece isn't into account when `include_sub_dirs` is present. Example:

```
- base: base.yml
  for_each:
    in: configs
    include_sub_dirs: true
    regexp: ".*.yml"
    except: [test.yml]
  to_dir: ++tmp/base_output/++
```

This can be solved with #46 
@herrjulz can you review pls? 