Add Ctrl>0 to return to default font size.

```
Currently Ctrl>+ and Ctrl>- can be used to increase and decrease the font size 
of the text in the editor.
You could even add Ctrl>0 to return the font size to its default.
```

Original issue reported on code.google.com by `ikramuddinmiu` on 4 Sep 2012 at 9:17
