Initial version of github_status plugin.

Very simple on-demand query of GitHub Status API.
https://status.github.com/api
GitHub Status overhaul: use HipChat API for colors, use instance methods.
Don't instantiate the GitHub status plugin.

* Rename plugin to match the command: hubstat
* Move logic to transform a GitHub status message to a chat room
  message into a simple Struct
Remove inner object to align with existing class-method-all-the-things design
Add config for hubstat plugin to customize in what room to post.
Merge pull request #35 from robbkidd/github-status-plugin

add GitHub status plugin