Don't make GitRepository a window global

src/app/git.coffee

@@ -1,6 +1,7 @@
 $ = require 'jquery'
 _ = require 'underscore'
 Subscriber = require 'subscriber'
+GitRepository = require 'git-repository'
 
 module.exports =
 class Git

src/app/window.coffee

@@ -11,7 +11,6 @@ Pasteboard = require 'pasteboard'
 require 'jquery-extensions'
 require 'underscore-extensions'
 require 'space-pen-extensions'
-require 'git-repository'
 
 windowAdditions =
   rootViewParentSelector: 'body'

src/stdlib/git-repository.coffee

@@ -1,4 +1,5 @@
-class window.GitRepository
+module.exports =
+class GitRepository
   constructor: (path) ->
     unless repo = $git.getRepository(path)
       throw new Error("No Git repository found searching path: " + path)