Mac-friendly changes

Had a couple problems running this from OS X:
1. Escape characters weren't working, so I switched `\e` to `\x1B`.
2. The regexp for yaml/yml wasn't working, so I simplified it. I also allowed it to check eyaml/eyml files, which are used with hiera-eyaml (https://github.com/TomPoulton/hiera-eyaml).

Let me know if you want these changes in separate requests.