Fix for "All" and "Last" history buttons

The history buttons were not working properly. They were referencing a capture variable `notices_data`, which got out of sync with the global collection of notices because $.merge returns a new instance on each pnotify call. Because of this, the buttons only worked on the first notification opened.

![image](https://f.cloud.github.com/assets/4964780/1912384/60211802-7d39-11e3-8ce6-3022d29d4ba1.png)