Fix deprecated '--join' option in the CoffeeScript 1.8.0

[see](https://github.com/jashkenas/coffeescript/commit/1cd48a9f5d38e823434c6c00ba41846270535a47)
or maybe reduce define variables in one line
``` python
cat, separator = ('type', ',') if platform.system() is 'Windows' else ('cat', ' ')
```
?