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

[see](https://github.com/jashkenas/coffeescript/commit/1cd48a9f5d38e823434c6c00ba41846270535a47)
We use relative paths when running ```run.py``` and I found no problems on Windows XP
![screen shot 2014-09-02 at 11 46 47 pm](https://cloud.githubusercontent.com/assets/47926/4124655/84510b5e-32da-11e4-84e1-2b42ed846b0c.png)
but I'm unable checking it on new Windows versions