Feature: More recent items

```
Make the parameter MAX_RECENT=5 within Recent.java into a settable preference 
allowing 2, 5, 10, 20, 50, or 100 recent items.

(I need 100 recent items with saved locations to easily use APV Pro as my main 
PDF reader; I swap between a lot of papers.)
```

Original issue reported on code.google.com by `yudkow...@gmail.com` on 15 Jul 2014 at 6:57
