End stdin on ctrl+d

Looks like Windows can't generate EOF, which prevents using `coco -s`

 - Should it be CTRL+D to be on par with unix ?
 - Should it be CTRL+Z because [Wiki said it was the code used back then](http://en.wikipedia.org/wiki/End-of-file)
 - maybe another way to track that ? this requires a CR currently.
 - do you not want that