Multistep Refactor, Renaming

[pearkes]

This was basically a complete re-write to play around with mitchellh/multistep and to learn a bit more about Go.

The steps package is pretty thoroughly tested, and contains various steps that are run by "runners", both from main.go (command line arguments) and from internal process.

Somewhat questionable that this project could have such high LOC seeing as it's doing a pretty trivial operation. That being said, it's cool to have error checking, GitHub OAuth, ignores, various other configurations.

Some to-do's before this branch is complete:

• [x] Binary build process for major platforms
• [x] Configuration checking, to make sure folks don't mess with their configurations

:walking:

[pearkes]

Skipping configuration checking for now -- want to get this out!