Title is off to the right in `presentation.isy` style

In `presentation.isy` I think the title should be a positioned at 608 (=640-32) rather than 640.

```diff
 <layout paper="1280 720" origin="32 0" frame="1216 648" skip="3
2" crop="no"/>
-<titlestyle pos="608 674" size="large" color="title"
+<titlestyle pos="640 674" size="large" color="title"
            halign="center" valign="baseline"/>
 </ipestyle>
```