added --js option to override autodetector when cs files are found

The generator detects if there are Coffeescript files in the /scripts directory. However, if one is following a guideline like this: http://briantford.com/blog/huuuuuge-angular-apps.html, wherein there are vendor directories inside the scripts directory that contain coffeescript files, then system should not assume that the user would like to create a coffeescript controller, etc.

I have added a --js option, unless, it is preferable to exclude vendors/ from the expanded search.