bbatsov/prelude — pull request #501 by wishbear (2014-03-26 12:46:31+00:00)
Title: don't enable coffee-cos mode if buffer filename is nil

Hi!
This PR fixes `magit-ediff` fail (by pressing `e` on a `.coffee`-file in `magit-status`):
`buffer-file-name` returns `nil` and `file-exists-p` fails.