Drum machine demo and the keyboard demo links are broken. 

```
https://code.google.com/p/mingus/source/browse/trunk/mingus_examples - drum 
machine

https://code.google.com/p/mingus/source/browse/trunk/mingus_examples - keyboard

```

Original issue reported on code.google.com by `diliupg` on 17 Mar 2014 at 12:46
