Add event-kit to exports

exports/atom.coffee

@@ -1,4 +1,5 @@
 {Point, Range} = require 'text-buffer'
+{Emitter, Disposable, CompositeDisposable} = require 'event-kit'
 {deprecate} = require 'grim'
 
 module.exports =
@@ -7,6 +8,9 @@ module.exports =
   GitRepository: require '../src/git-repository'
   Point: Point
   Range: Range
+  Emitter: Emitter
+  Disposable: Disposable
+  CompositeDisposable: CompositeDisposable
 
 # The following classes can't be used from a Task handler and should therefore
 # only be exported when not running as a child node process