Ability to read config.yml from the app root directory path

[fuss86]

This PR allows to read config.yml from the application root path as a fallback location.

Example:
node /path/to/main/script.js will read /path/to/main/config.yml if the config-yml module was located in /path/to/main/node_modules/config-yml

[coveralls]

Coverage decreased (-0.8%) to 93.548% when pulling b58d04a on fuss86:app_root_config_yml into 0b1a23e on Nordstrom:master.

[andyday]

It already loads config.yml from the app root. If its not working for you can you provide more details of your usage?

[fuss86]

If you run the node process from outside of the app root (for example from the / directory) then fs.existsSync('config.yml') will try to lookup config.yml from the working directory (which may not be the app root directory) (e.g. /config.yml, following the example).