Add getNotifications()

src/notification-manager.coffee

@@ -42,3 +42,9 @@ class NotificationManager
     @notifications.push(notification)
     @emitter.emit('did-add-notification', notification)
     notification
+
+  ###
+  Section: Getting Notifications
+  ###
+
+  getNotifications: -> @notifications

src/notification.coffee

@@ -28,7 +28,7 @@ class Notification
       and @getDetail() == other.getDetail()
 
   dismiss: ->
-    return unless @isDismissable()
+    return unless @isDismissable() and not @isDismissed()
     @dismissed = true
     @emitter.emit 'did-dismiss'