rc is awesome!

It's a tiny thing, but it would be great if the config file logic would permit .json and .ini extensions. In other words, looking for .${appname}rc, .${appname}rc.json or .${appname}rc.ini in all the usual places.

Definitely helps with triggering syntax highlighting in your editor of choice.

This idea was mentioned in #71, but since the scope of this feature request is far smaller in scope, I've opened it as a separate issue.