Support windows

i want to be able to open a repo in GHfW from the Atom text editor. There seems to be a protocol they install in the registry (?), but i need to do more research on it.

Examples of protocols via the GitHub.com site:

* Open a repo: `github-windows://openRepo/#{repoGitHubUrl}`
* With branch query: `github-windows://openRepo/#{repoGitHubUrl}?branch=#{branchName}`