Consider adding support for hjson.

[howardroark]

I'm going to delete the fork I have setup. That may close the pull request automatically. Let's consider this issue a place holder for the conversation.

Project link: http://laktak.github.io/hjson/
Mime type: text/hjson
File extension: hjson

Cross referencing some concerns:
hjson/hjson#12

Thanks!

[broofa]

node-mime now sits on top of https://github.com/jshttp/mime-db. Please submit requests for new types there. Thanks!