Queue

[CleverLemming1337]

I implemented a queue for NotificationPresenter and some functions to add, present and delete notifications in the queue.

At the end of the ExampleScreen I created a section to control the queue.

The variable ExampleScreen.queueContent is just for demonstrating and debugging. The counter in the queue section is quite buggy and can be removed as well as queueContent if you want.

@calimarkus I can change NotificationPresenter.present that it adds the notifications to the queue instead of presenting them directly if you want.